Teemo

No more mistakes going forward!  Way too important to make silly mistakes. Triplecheck everything. Luckily this shouldn't cost you anything, in the AOS interview they'll ask you to correct it. 

I don’t think you have anything to worry about here.
I have attended several interviews and we always prep for them.  
 
This is my number one prep reminder.  No matter the question ”I don’t know” and “I’m not sure” and “I remember this detail but not that detail” and “I don’t remember” ARE ok answers.  For us?  The interviewer often turns from her to me.  I’m an incident investigator among other things.  I give the facts I know and nothing else.  Nobody rattles me. 
 
A common mistake?  Providing an inaccurate answer to something the interviewer has in front of them with the goal of “impressing the interviewer” by filling in every blank at any price which is NOT the point of the interview.   They get you then.  It does not sound like you guys made this what could be “fatal” error.
 
Good luck!

That happened to me. My GC was approved when I was out of the US. I showed up with AP and was admitted as LPR. The standard operating procedure for someone showing up with AP is to go to secondary to verify if there is still a pending I-485 or not and if they see the I-485 is approved then they admit as LPR.

All they care about is the EAD/AP card. They don't talk about Matter of Arabally, they just know it. They just stamp you and send you on your way. 

It isn't a big deal.  Your information will be retrieved by your A number and the CBP will see that the card was recently produced.  If the ask just say it didn't come before you left.

A legitimate reason for changing one’s mind is not a requisite for AOS.

A green card is only evidence of your LPR status. Once AOS is approved, you are an LPR. If somebody made it to the border (i.e. by land since boarding a flight might not be possible w/o a valid documentation) with only documentation of their identity (i.e. a passport and no green card), CBP should be able to see that they are an LPR and admit them as such anyway. It might not be a fun or quick trip, but the green card isn't actually needed for admission.
 
If the officer isn't paying attention, it's possible they could parole you into the US. Being a parolee theoretically could be an issue in the event of removal proceedings (if something were to happen down the road). Lookup parole vs admission for some good readings if you're interested. It's just simpler, IMHO, to know that you were admitted instead of paroled.

It would be preferred to just get an I-551 stamp if possible, but a valid AP would work to board the flight then CBP could see they are an LPR.

I researched the heck out of this and am very comfortable with Matter of Arabally.  I was a significant visa overstay. Married USC, got AP. I then used AP 7 times. 4x for work to Canada, 3x for vacation. All times had to go to secondary inspection. All were routine. Entered with no problem all 7 times. Just don't present any sort of security risk and don't commit a crime while abroad. 
 
I asked about 10 lawyers and about 4 of them said not to go and had no idea what Matter of Arabally is. Moral of the story is there are a lot of bad immigration lawyers out there (or maybe they are good but don't want to learn new things post law school)
 
 

I think that's the typical interview method. I learned from different posts that the IO will repeat the question to testify the answer is real or not. 
I thin OP is fine. Don't worry too much. Your green card is on the way. Hope you can get it before your trip. 

It doesn't jump out to me as a reason to be overly concerned. Take a breather...I think you're worrying more than you need to.
 
There is always a risk of not being re-admitted with AP. That said, the risk is generally very, very small, and applies to anybody. So it is safer to not leave the US.
Personally, though, I wouldn't change my plans for a short vacation based on the above.

No, you'll be let in (well, under the same process as any LPR). If you are aware of approval already, it might not hurt to just make request that the CBP officer admit you as a permanent resident instead of potentially paroling you into the US.
I did ask this specific question to the IO at my wife's AOS interview.

I researched the heck out of this and am very comfortable with Matter of Arabally.  I was a significant visa overstay. Married USC, got AP. I then used AP 7 times. 4x for work to Canada, 3x for vacation. All times had to go to secondary inspection. All were routine. Entered with no problem all 7 times. Just don't present any sort of security risk and don't commit a crime while abroad. 
 
I asked about 10 lawyers and about 4 of them said not to go and had no idea what Matter of Arabally is. Moral of the story is there are a lot of bad immigration lawyers out there (or maybe they are good but don't want to learn new things post law school)
 
 

I researched the heck out of this and am very comfortable with Matter of Arabally.  I was a significant visa overstay. Married USC, got AP. I then used AP 7 times. 4x for work to Canada, 3x for vacation. All times had to go to secondary inspection. All were routine. Entered with no problem all 7 times. Just don't present any sort of security risk and don't commit a crime while abroad. 
 
I asked about 10 lawyers and about 4 of them said not to go and had no idea what Matter of Arabally is. Moral of the story is there are a lot of bad immigration lawyers out there (or maybe they are good but don't want to learn new things post law school)
 
 

Your age difference may have been a red flag to the CO, but you overcame it with evidence of 7 years living together. OP does not have that, and thus the statement "your age difference is not a determining factor" is more specific to your situation and not general advice. Yes, I note that you say "in my personal experience" but just want to reiterate that this depends on the totality of circumstances, which were more compelling in your case than OP's. 

Based on the details given, IMO the most likely reason he was denied was not based on your relationship, but because they suspect he might be using you to get the green card - ie pretend he is in love and scam you into petitioning for him. I am sure that is very insulting to you. Nevertheless, in  acountry like Morocco where this is somewhat common they have certain things that they look for and ask in this type of scenario ("why are you marrying someone who doesn't understand your culture") and your fiance probably failed at least one of these questions.  
 
Nicole & Azan probably did Morocco no favors either. 

They do a security check on both petitioner and beneficiary, and it has nothing to do with living in the US or coming back for one month a year. They can do one on people living anywhere in the world, although of course it is easier to get in some parts of the world than others. The US shares and receives information widely with other governments. So first, you should stop assuming it's necessarily you the security check concerns, and your 1 month in the US a year has nothing to do with it (unless of course you have been busted smuggling stuff to the US in that time). The reason they do the security check on you, the US citizen, is that under the Adam Walsh Act if the US citizen poses a danger to the beneficiary (ie domestic violence, convicted of having sex with a minor etc) they won't approve the petition. But if you don't have that issue, then I'm willing to bet it's the beneficiary that the security check is held up on, does he have anything in his background, especially political, that China would have on him? Was he arrested of same sex/sodomy issues and maybe that's the problem? (sorry if that's insulting I just don't know how the law works over there)
 
Cancelling your current fiance visa and filing spousal visa wouldn't solve the problem, as security checks are needed there too so you'd just have the same issue. He likely can't get a tourist visa either if a security check is still pending. Continuing to just wait patiently isn't the best option either, since 3 years is about 4x as long as it should take. 
 
So yes I think your best bet is 1) contact the ombudsman, supposed to be a neutral party (www.dhs.gov/topic/cis-ombudsman); 2) update your congressman and have them inquire again; 3) request a FOIA (www.uscis.gov/g-639) to get all the info on your case - it's free; 4) call USCIS again and again and ask to speak to tier 2 representative; 5) make an infopass appointment to try and hurry them along (https://my.uscis.gov/appointment); 6) absolutely start the process of filing court action against them. I've seen a couple cases where just the threat of this speeds them along. 
 
Good luck! Very awful situation they have put you in. 
All states recognize same sex marriage now
 
CR1 would not solve the problem of security checks, so that process would be held up too. Issue of domicile would not hold up security checks; besides, US citizens live all around the world and they are entitled to same rights that US citizens in the US receive. Petitioner/OP has a connection to the US - he is a citizen there. That is the only connection the petitioner needs - he has free and total right of entry and residency in the US. The issue in terms of this application is that the petitioner must prove he will move back to the US before or at the same time as the beneficiary, so at some point he will need to provide evidence of where he will live, work etc. But the application hasn't even progressed to that point, it is still stuck on the security checks! So that's not the issue since they need to interview him to get that info, and then they would approve/deny him on this basis, not simply hold it up for 3 years. 
 
Many US citizens live around the world and they apply for immigration benefits for partners all the time, when they are ready to move back to the US together. There is no rule or custom that only US citizens living in the US can apply or else face large delays, USCIS are fully capable of processing those cases in almost all cases. So most likely situation here is some issue in the beneficiary's background that China is being tight-lipped on causing the hold-up, because OP would know if something in his own background could be flagged as a national security or public safety threat. 

Don't mean to sound insulting but you should be wary of a change in attitude as soon as the residency opportunity she depends on you for has been taken away. That sounds like conditional love to me.  At the very least you should give it some time - but yes if you decide to go through with it you can adjust her status in the US with the same docs you originally filed (I-485, etc)

The obstacle you will have to surmount, over and above the proof of a valid relationship, is the idea that he is just pretending to be in love with you to get the green card, then all of a sudden you will have "marital problems" and divorce. The issue is that that is actually somewhat common, and many of those cases have features in common that are present in yours. This week alone I have seen many denials on this forum from Ghana, Morocco, and other countries that are considered "high fraud." Because, there is a high level of this kind of stuff going on. 
 
Honestly the show 90 Day Fiancee makes this process even worse, because there are some couples on there where this is definitely happening and we get to peek into their relationships. The US citizen feels he/she is in love, and that person loves them back, and they are in a bona fide relationship as evidenced by chats and family support, and then....at the first second the beneficiary is able to leave he sometimes does (I'm looking at you Mohammed). 
 
Of course, comparing your relationship to a trashy TV show is insulting and does you a disservice. But, you have to see it from their point of view. How will you guys overcome the presumption of "He is scamming her to get a green card?" That is demonstrably harder to overcome than "Is this a real relationship?"
 
That is why you are getting the advice to spend lots of face to face time together. Because the standard will be that high. Good luck. 

Yes, a ton of people. Advance parole is an established procedure used hundreds of times a day. It's not guaranteed there will be no complications, as only US Citizens are guaranteed entry to the US, but if you haven't committed a crime since being granted AP or lied about something material, or bring something prohibited back with you like drugs, then it's most likely your spouse will be granted parole back into the US. 
 
I have traveled on it myself and had to spend some time in secondary processing at the PoE but it was routine.  I also found dozens of success stories online and talked to 5 lawyers just to feel comfortable (because it is a scary thing) and I got a lot of comfort from them. 

It is standard protocol and widely-known that a blank "employment end date" means you are at that job currently. 
 
Btw, I did not fill out any employment info whatsoever and got approved for my EAD/AP in a timely fashion.
 
The chance you would get an RFE for leaving an employment end date blank is exactly 0.00000%. Don't worry so much.  

I certainly don't want to wade into a political debate, and there is very likely some things that have improved in the immigration system recently. But it is undoubtable that the processing times have DRAMATICALLY slowed down in the last 1-1.5 years, even as prices have gone up. 
 
That's not even a criticism btw, it's possible that they are doing a better/more thorough job than they did before and that is what is needed. 

AP is averaging 3-5 months right now. I got mine in exactly 4 months earlier this year.
 
In terms of processing times, look up the I-765 at the National Benefits Center (NBC) for their estimate of when you get employment authorization/advance parole but I don't think they are very accurate. For the actual interview, look up the I-485 with your local field office, in your case Boston. It is saying 8.5 Months to 24.5 Months, but again I do not think they are very accurate. For busy field offices, it is looking like 12-14 months. 

EAD (work permit) & advance parole (for traveling and re-entering the country) for AOS applicants are processed through the NBC. EAD is taking 3-5 months on average to process. I got mine in exactly 4 months earlier this year. 

I am sorry to hear that, but I am glad you found out at this point and not further along in the process (ie after the green card). I think there are many people who may, on some level, suspect they are being scammed but do not want to admit it to themselves, much less others, so I admire you for being able to do that. Yes, you can and should report suspected marriage fraud to USCIS and/or ICE. Just make sure there is no evidence that you were knowingly part of the scam, which I am sure is the case. 
 
There are sometimes people on this forum who have unknowingly entered romance scams or perhaps suspect they are, any information you can give about your experience and the signs of a romance scam will surely be helpful to others. Personally I see signs of it on this forum but no one will ever listen to reason when they are in love  So you have more credibility in terms of conveying that info. 
 
Best wishes to you.