I can't really answer some of your questions. But, if your spouse is a UKC, then you would select married filing separately and just write non-resident alien where it asks for a social security number. You wouldn't need to list any income for your spouse, only your own.
As you haven't earned any income in the UK, I would think you should file as you usually would. I'm not sure of the specifics, as my situation differs from yours. But if you have your W-2s and understand which forms to use for student loan payments and interest, then you should be able to just fill these items in on your tax form and go from there. As far as state taxes go, I have no idea, as I am from Texas and don't pay state taxes.
Sorry I couldn't be of more help. Maybe someone else will come along who is better with taxes. I just read the booklets and struggle through.