accumbyte

Not what @WeGuyGal was referring to. The MRIV usually has the following text on it: "UPON ENDORSEMENT SERVES AS TEMPORARY I-551 EVIDENCING PERMANENT RESIDENCE FOR 1 YEAR" not 2 years: https://www.uscis.gov/i-9-central/temporary-i-551-stamps-and-mrivs

* Moved from Progress Reports to Process & Procedures *
 
1) Was he still married at the time the I-129F was filed? If so, this is a very significant issue.
2) He must disclose the past marriage on the DS-160. The CO will likely notice the discrepancy and request the divorce certificate. The only unknown is whether that is the end of it or if the CO will send the I-129F back to USCIS as it was incorrectly approved due to the incorrect information on the petition and lack of required documentation to go with that.
Edit: Technically a misrep bar could come into play, but I'm personally doubtful of that if disclosed voluntarily (while negligent in verifying the accuracy of the I-129F before signing and sending it, I would find it hard to believe somebody would claim it was willful if disclosed on their own).

Yup. The overstay does not incur a bar upon exit so long as you have a valid AP document, and it doesn't mean anything upon re-entry attempt.

Can CBP decline entry? Yes. But there are not reported cases of them doing so for a properly issued and still valid AP. The most likely reason for refusal would be if AOS is denied while abroad (making AP invalid), they commit crimes abroad, they try to smuggle something (or someone) into the US, etc.
People travel on AP every day.

CBP officers are not likely to refuse entry because of "sour mood."  The discretion to deny entry to anyone who is not a USC is there for our protection.  
 
In all likelihood, a person with a valid AP would not be denied unless something had happened in the interim since it was issued.....being placed on a watch list, being wanted for committing a crime, or saying/doing/importing something out of the norm at the POE.

If your wife has a valid advance parole document, she is unlikely to have any major issues re-entering the US.  AP documents are used every day by immigrants to enter the US.  Of course, only US citizens are guaranteed entry.

Because it's fast and in the eyes of USCIS, perfectly legal.  We did ours in Hong Kong because I didn't want to sit around the Philippines for 4 to 6 weeks to get it done.

Deferred Action for Childhood Arrivals does not grant lawful status but does provide lawful presence; https://www.uscis.gov/archive/frequently-asked-questions:
 
For future reference, USCIS definition of Immediate Relative is very limited: https://www.uscis.gov/tools/glossary/immediate-relatives

Deferred Action for Childhood Arrivals does not grant lawful status but does provide lawful presence; https://www.uscis.gov/archive/frequently-asked-questions:
 
For future reference, USCIS definition of Immediate Relative is very limited: https://www.uscis.gov/tools/glossary/immediate-relatives

DACA recipients don't accrue unlawful presence. This differs from having an actual lawful status, though.
 
While archived (DACA status itself is in the process of being terminated, for the lack of other phrasing given the legal process involved)
https://www.uscis.gov/archive/frequently-asked-questions
" Q1: What is deferred action?
A1: Deferred action is a discretionary determination to defer a removal action of an individual as an act of prosecutorial discretion. For purposes of future inadmissibility based upon unlawful presence, an individual whose case has been deferred is not considered to be unlawfully present during the period in which deferred action is in effect. "

Just a note that a sibling does not qualify as a relative for the I-601A. But a parent does.
 
That would be a possibility to avoid needing a waiver...unlawful presence only accrues from age 18 onward, and does not accrue while covered by DACA.
 
Incorrect. Siblings are never considered an IR.
Edit: This would apply to a parent, but given the details thus far, I don't think this applies.

Even if the "marriage" was not official or recognized, you're definitely tiptoeing on the the line. As others stated, people have been denied a K-1 for similar and lesser celebrations.
It sounds like the K-1 was already issued. That said, that doesn't negate any of the above. If CBP or USICS ever discover a prior marriage, it could create problems down the line if they determine the K-1 was issued incorrectly. Any subsequent benefits obtained would be at risk.

The marriage certificate needs to be submitted with the AOS packet. The I-131 and I-765 are filed alongside AOS.
 
If waiting until after the Sept. obligations are complete is a viable option, you can contact the embassy and see if they would be willing to cancel the K-1 visa and issue another one later. A new medical would be required, but it's a possibility. Not all COs may be open to doing so.
 
 
 

I should rephrase that. The only ways to lose your citizenship of Australia as a dual citizen, is if you’re someone who breaks serious laws OR if you choose to renounce it. The US does not require you to renounce it for citizenship, nor does Australia.

That info is outdated for now. All visa applications (except diplomatic) that were pending in Havana were cancelled: https://cu.usembassy.gov/frequently-asked-questions/ It could change in the future, but right now if a Cuban is at the NVC stage and the USC's petition listed Havana then NVC automatically assigns the case to Georgetown, Guyana.

Maintaining a green card means maintaining permanent residency. If you are abandoning permanent residency within the US, then there is no need for a green card.
 
What I would highly suggest for your circumstances is to obtain US citizenship before moving. Then you don't have to maintain US residency and can come/go whenever you want.
You should qualify to apply under the 3 year rule since you are still married to a USC. Given that you are already in ROC, that means there should be less than a year before you can apply. They normally adjudicate both the I-751 and N-400 together if you apply while ROC is still pending.

Correct.  File a separate petition for the child but the I-864's will come at the NVC stage, not with the petition.

K1 is shorter by a few months to visa.  In general it's about twice as long to green card and work authorization is taking about 6 months.  So that means after arrival, marriage, and filing AOS, it takes about 6 months before the beneficiary can travel outside the USA or even work. 
 
If you're self employed then your current income is based on your latest tax return.  So 2018 will determine your current income.  This is not like a normal w2 income. 

You would need an I-360 for VAWA then a new I-485 as the current one is denied.

USCIS also accepts credit cards and debit cards: https://www.uscis.gov/news/news-releases/uscis-expands-credit-card-payment-option-fees

Honestly, the I-485 is a much simpler process than the K-1 visa IMO.
There's more direct forms needed to complete and submit, but you basically just fill them out, provide the necessary documentation, and wait for an interview.
 
Anyway, read through the guide (https://www.visajourney.com/content/k1k3aos) and instructions for each form. Ask questions. If you still don't understand or have particular concerns, then professional assistance may be useful.

Like I said before, the first table, so A. No matter when you can file documents, you can’t actually get a visa until the date in table A is after your priority date.

no necessarily, the person can also be a legal permanent resident

I second this. Call the USCIS office in Frankfurt up directly, explain the situation and ask if it will be accepted as proof of residency.
 
When I did DCF, I called the local office and they were glad to answer any questions I had. You could also try emailing but it might be slower.
 
I wanted to add, if you decide to call and do get answer, please update us on what they say! Best of luck.

See "Form I-130, Petition for an Alien Relative" section on the USCIS Frankfurt page: https://www.uscis.gov/about-us/find-uscis-office/international-offices/germany-frankfurt-field-office
You can try asking the Frankfurt office directly as they are the ones that make that decision: https://www.uscis.gov/about-us/find-uscis-office/international-offices/contact-us-uscis-frankfurt-field-office