Only immigration judge can "cancel" her GC.
Looks like your marriage didn't work out, I'm sorry about it. As far as splitting assets etc, treat it like any other marriage to US born citizen, because it's not different to that.
Cost of living increased significantly over the last few years. USCIS held the fees unchanged for some time. All of the slowness is a result of underfunding for the last few years. Maybe if USCIS doubled the fees they'd have money to invest and speed up processes....
Hang in there, July to November is only 4 months. Many petitions take year and over.
If hiring lawyer, why not hire for entire process? From filing to oath.
I'm not sure how many lawyers would go just to your interview. They need to know your case, circumstances etc.
Few days and even a week or two won't make much difference. My friend filed I-751 3 weeks after me and got approved 4 months earlier. Everybody who filed on my week were delayed. You never know whether filing today or tomorrow will give you faster adjudication, it's unpredictable. Risking the whole petition by filing on first day isn't worth it.
They're highly recommended.
The point of including tax return transcripts is to show that you pay taxes as required by lawful permanent resident. If you have a valid reason to file MFS it's OK.
If you have valid GC, the chances of you getting in without issues are high.
The biggest hurdle tends to be the airline. If you have valid documentation, you should be OK.
You likely going to get a warning from CBP and maybe would have to visit the secondary. But most likely they'll let you in.
Make sure to limit the international travel after entry to the US and naturalize to get full freedom of movement.
He can apply for reentry permit which h will allow him to stay outside the US for 2 years without losing LPR status.
How long is he going to continue studies overseas? If more than 2 years this may be challenging.
How so? In the event USCIS only conducts I-751 interview on the day, your N-400 will remain pending and they'll call you for N-400 interview later. No issue there. You won't lose money.
Are you sure your lawyer is a real immigration lawyer?
I don't know where you get this info from.
"U.S. law does not require a U.S. citizen to choose between U.S. citizenship and another (foreign) nationality (or nationalities). A U.S. citizen may naturalize in a foreign state without any risk to their U.S. citizenship. "
Source:
https://travel.state.gov/content/travel/en/legal/travel-legal-considerations/Relinquishing-US-Nationality/Dual-Nationality.html