You do not have to be separated to use MFS. It's a tax strategy which is perfectly legal. It's used when one spouse has a lot of deductions for medical charges for example.
Single or Married File Separate? I hope you're not using the terms interchangeably. They mean different things, and again you don't have to be separated to use MFS.
MFS only works for some situations. MFJ works for majority cases.
@Crazy Cat's wife did it. You'll either get I-751 approved before N-400 interview, or you will have an RFE or interview for I-751 on same or different day.
Pretty much, similar to filing under 3 year rule in this case. Only you have less evidence to provide for N-400 itself.
@dleen congratulations with immigration journey coming to the end! Thank you for sharing the experience in great detail. Why were you surprised to get a combo I-751 & N-400? Everybody with pending ROC should expect it, though it's not guaranteed to happen.
You didn't have a lawyer present, did you? The questions about your wife's health was ridiculous and unnecessary.
Alien Number appears on various documents, including immigrant visa, some student visas, Green Card etc. Does your friend have Alien Number? If not, there's nothing to provide.
You're going to be fine. Make sure you file it with payment this time. Double check all the versions of forms, some may have been updated, so you need to include new forms.
Children could become naturalized whenever he becomes a US citizen. But that only works if they live in his custody in the US. So he could sponsor them for Green Cards now as a father. Did he list them in his immigration paperwork? If not, it's a big problem.
Please focus on divorce and moving on. I-751 was filed by LPR and it's their problem to remove conditions. It's their responsibility to notify USCIS about divorce and change petition (or file new) to divorce waiver. As long as enough evidence of bonafide marriage was submitted with petition, there's nothing you can or should do when it comes to USCIS.
The I-864 is still in place, however. This means you can be liable for them until the LPR naturalizes or they earn 40 quarters of work with Social Security.
I travelled by air in December, there was no problem. My passport also required visa or eTA for Canada, but I didn't have to apply for it because of GC and extension letter.
Can you go back in time and change anything? Probably not. So why worry about the things you cannot control?
Try applying and see what the outcome would be.
Since you haven't been charged with a crime, I don't see it as a problem. Be honest if any questions are asked.
Was he ever listed on your immigration forms as a parent?
Is he on your birth certificate?
If answers to both questions are "yes", then follow the guide, you have nothing to worry about. If the answer is no to any of these questions, there may be a complication.
All the answers can be found in the guide. Affidavit of support is relevant when I-130 is approved and you're at NVC stage. For now you're just waiting.
Good luck!