GreatDane

USCIS isn't necessarily going to be satisfied that the IRS has issued an extension. It's the beauty of different organizations having different standards. They will want the most recent tax information. It is up to the CO processing your case. It could come down to paying the taxes owed and becoming up to date or delaying/resubmitting your petition. 

My husband always says - money can always be made. The rest is what matters. 5 years from now, you won't care so much about the money you spent. Does it suck? Absolutely. We've spent more on things during our process than we'd have liked. But what I CAN guarantee you, is that once you are together for good, everything you've done will be worth it. Just hang in there - you don't have much longer to go with your K1.

Disregard but keep the letters for your record. They aren't valid as you no longer have the original green cards. Renew the I551s when they are within 30 days of expiring. 

Offices vary with taking the green card. There's another VJ'er who is in the same step in the process and had to get an I551 stamp the same week as me at the same office. They took mine and he kept his. Don't stress about them taking it - it doesn't have an effect on the process. 
I would proceed with the I551 being the valid document as proof of residency, etc. It will expire on the date listed on it (typically either six or 12 months). You should be 100% ok to travel with the I551 stamp.

Just because you are hearing something other than what you want to hear doesnt mean people don't support you or want to help. 
 
You withdrew your initial support of the I-129F.  You can't cancel that withdrawal of support. It really is in your relationship, self, and fiance's best interest to make sure the current I-129F is fully cancelled and to start over.   While this isn't what you want to do, it will save any heartache later and ensure a smoother process overall.  You can obviously continue on your current course if you choose.  If so I suggest asking a mod to close this thread so that do not continue to get advice you don't want to hear. 
 
I suggest rereading the TOS again as well.  

It is not a current program offered - it stopped being offered in 2012. K1/CR1 is the best option for your case.
 
A provision of the Lautenberg Amendment to the Foreign Operations Appropriations Act previously allowed certain religious minorities from the former Soviet Union, Estonia, Latvia, or Lithuania who were denied refugee status and subsequently paroled into the United States on a humanitarian basis to apply for lawful permanent resident status (green card) after acquiring one year of physical presence in the United States, without regard to visa availability.
This provision expired after Sept. 30, 2011 and USCIS announced in July 2011 that it had stopped authorizing parole for new applicants under the program to ensure that all individuals who were authorized parole under this program would be able to travel to the United States by the deadline. Though the Lautenberg program was later renewed by Congress, USCIS, as a matter of policy, has not re-started the parole program.   Individuals who had been offered parole under this provision were required to arrive in the United States by Sept. 30, 2011, though this deadline to travel was later extended to September 30, 2012. 

Even having enough to be above the required 100%, the embassy may not approve just because they’ll be looking at AOS and think you’re not gonna be able to provide. Some embassies deny even if you have enough just because you are super close they think you might be a risk. They might not deny you, most likely they’ll ask for a sponsor before they move on. Some embassies don’t allow foreign income, so what the beneficiary brings might not be considered. If you’re using assets remember it’s 3x 125%. My personal opinion is they’re not gonna accept your current income as is and they’re gonna ask for a co-sponsor. I would start shopping for another. 

I think it is much more than sufficient. The only thing we included that isn't already listed was a copy of car titles and life insurance policies, showing each other as the beneficiaries. That being said, you have definitely front loaded your petition. Just make sure to make a copy for yourself in case you're asked about it at the interview.

This would be fraud. You cannot enter the US with intent to AOS. If you want to do it, you need to do it while in the US. You cannot leave and return to do AOS.
Edit: This may sound harsh, but this immigration policy differs from Canada where such actions are permitted.
 
It means you would need to interview for an immigrant visa in Montreal instead of completing the green card process via AOS within the US.

Yeah - I had something similar happen, albeit a year ago, and I know it's happened for credit score information, too. Basically, I didn't have enough background, employment or financial, in the US to verify me through the regular/automatic process so they had to do it manually. It worked out 100% in the end, but took a bit more time.

I always send with USPS with tracking and signature confirmation.

I believe that is the case here, but there are some countries that will not allow you to emigrate with certain financial obligations. A personal loan is not one that ever seemed to be an issue, though...it's usually taxes, child or spousal support, etc.

Send your information ASAP. Remember that the September 11th date is approaching and with that, change to the RFE procedure. Starting September 11th, there will no longer be RFEs - just denials with the ability to reapply and the clock will start over. Get all your paperwork in so it can be processed as soon as possible.

Oops. Looks like UK isn't part of Schengen agreement.

Not wanting to play devil’s advocate here, but......  She has lived her open LGBT and atheist lifestyle since 2015 via Twitter. So she has not lived this lifestyle in a real scenario?  She is in extreme danger in her country as a result of this? You have known her for years, but have never met her in person?  It is customary in her culture to get married soon after meeting, but her family would never approve?  This sounds like a big struggle for you to convince anyone that you two have a bona fide relationship. Best of luck to you and may she stay safe.

So after 3 years what is the issue now?

I'm kind of shocked that you don't know each other in person, you're willing to believe everything the other person says - and it sounds like a lot, and you're willing to go through a lot of possibly finanancial burden and time on someone whose face you have never seen in real life. Visa fees, AOS fees, medical fees, lawyer fees... this will pile up. 
 
Honestly? Before you commit yourself to anything meet in person first. You're not the first person blinded by love but be aware that it's very easy to scam someone online. 
 
And another option- DCF for k1 doesn't exist. Asylum in China I doubt it will happen. Humanitarian expedite probably won't happen either. 
 
Meet in person and do normal k1 or cr1 route and wait your time - you can try expedite but I don't think there is much chance there either. Reality is harsh  

She is bisexual. The atheism alone is enough for asylum and most counties in Europe being a woman in Saudi alone is enough.

At this point, resubmit with a co-sponsor and include the most recent financial documents. Knock everything out at once. It's not advisable to quit a job, especially with a pending petition and not sure whether there's the option for a co-sponsor. Cross your fingers that his mom will co-sponsor.

At this point, resubmit with a co-sponsor and include the most recent financial documents. Knock everything out at once. It's not advisable to quit a job, especially with a pending petition and not sure whether there's the option for a co-sponsor. Cross your fingers that his mom will co-sponsor.

Did he quit his job for another job and is currently employed by a new firm? It's not a good time to be unemployed for your immigration status. If he's unemployed, he should find a new job and fast. Does he receive any disability or continuing financial benefits from his time with the military? Does he have the ability to find a co-sponsor?

Is he currently employed and has had sustained employment? Does he have any children, even if they don't live with him? Did you attach 3+ years of returns?

At this point, resubmit with a co-sponsor and include the most recent financial documents. Knock everything out at once. It's not advisable to quit a job, especially with a pending petition and not sure whether there's the option for a co-sponsor. Cross your fingers that his mom will co-sponsor.

At this point, resubmit with a co-sponsor and include the most recent financial documents. Knock everything out at once. It's not advisable to quit a job, especially with a pending petition and not sure whether there's the option for a co-sponsor. Cross your fingers that his mom will co-sponsor.

No.
That said, trying to figure out why it was not accepted previously is basically a moot point. He would have to submit a new one now and he no longer has a job and therefore has no income from it (although unemployment compensation can be listed, but if he quit the job then I'm assuming even that doesn't apply).