Hi all, hope I can get some helpful insight from knowledgeable people on this forum.
Facts:
1) Green card holder has been a permanent resident since 2/2007. Willing to apply for US citizenship 90 days before 5 years period passes (12/2011).
2) It is understood that after application by green card holder it may take some time (how long?) before citizenship is granted.
3) Girlfriend came to the US on F-1 (legal entry) a year ago. Expected study completion - 5/2011. Then will apply for OTP (for one year), so legal status until 5/2012 (is this correct?).
4) Green card holder and F-1 are engaged (also, baby expected 12/2010) and live together (having been living since F-1 arrived in the US).
5) State of current residence is IN.
6) F-1 also has a US citizen sister who filed citizenship application for F-1 about 2 years ago (expected time for F-1 to get permanent residence via this route is about 4-5 years).
What is the best way from the legal standpoint to approach permanent residence for F-1? Options I can think of:
A) Get married now and apply for change of status after marriage asap. In this case, will the marriage and filing to AOS affect F-1's ability to maintain F-1 and obtain OPT (so that F-1 can stay in the US legally until F-1 obtains other status and if so, what that status can be)?
B) Wait until green card holder becomes US citizen and then get married and file for AOS for F-1 at that point? In this case if AOS is filed and OPT expires, will ex-F-1 (ex at this point as OPT is expired) legally stay here or it will be illegal already?
C) Any other option?
Thank you!

