It's hard to create a ranked list of topics b/c it varies from one exam to the next. The exam is VERY comprehensive overall, so almost anything is fair game. In general terms, some of the larger topics are: OB/GYN, Peds, GI, Cardiology, ER/Trauma, ID, Pulm, Renal, Neuro.
I would answer your 3rd question with a RESOUNDING YES!!! OB/GYN tends to be covered very heavily and, thus, the 1st 40+ pages of FA would be WELL worth your time!!!! If you neglect OB/GYN, you're going to have a very hard time with the exam!
This is one of those exams where it's hard to skip on any section, b/c there's a chance that the one section you did not study for is tested often. Of course, you'll want to giver preference to, say, Peds over Rheum, but they can and do ask any and everything. I recommend knowing FA well and maybe supplementing it with Deja and QBank. Good luck!
