In depth questions regarding Navy ratings (jobs)?

Before I start, I'll answer a few basic questions that some people are bound to ask. Yes, I'm enlisted (woo-hoo!!!), I scored an 83 on the ASVAB & I have a ship date to boot camp (Feb '13) & a rating (IC), but it's not necessarily the rating that I'm seeking (HM). I have also been informed that I have the oppurtunity to leave in Nov of this year as a Pact Seaman. Just so you guys know, I am not just joining the Navy for the educational benefits; that's just a bonus that I plan on taking full advantage of. My priority is to serve the country that I live in (: I've talked to my recruiter & several others about my questions & concerns, but they insist on answering like car salesmen rather than realist. I am informed on both the pros & cons of the navy & I am 100% committed despite the cons. So, with all of that being said, here we go:

1) As I stated, the rating that I'm most interested in is HM (hospital corpsman), but according to the classifier that I spoke to at MEPS & my recruiter, it is a hard rating to come by (it's overmanned) & they do not know the ship dates before hand. I have an interest in HM because of the civilian jobs that it translates to & I am shooting for a M.D. in the future. Based on my research, I've read/heard that females are not necessarily chosen for such ratings. Based on your knowledge, is that true?
2) I am in DEP. If my recruiter were to send in a DAR for HM, would I lose my current rating? What is the average wait period before shipping out to boot camp as an HM?
3) I am adamant about going into boot camp with a guaranteed spot in A-school for HM, but the unknown wait for a ship out date is what has me considering going in a as Pact Seaman & striking for the HM rating. How long would I have to serve as a Pact Seaman before I could strike for HM & what are the steps in doing so?
4) Would you advise me to go into boot camp as a Pact Seaman? Why or why not? (Once again, I am aware of the cons, so please don't just try to sell me the pros).
5) I've heard that some sailors who are Pact Seamen were kicked out of A-school. Does that mean that I would potentially be looked down upon if I went in as one?
6) Being a HM in the Navy would be beneficial to me because even if I didn't have much free time to complete college courses towards my M.D., as a HM, I'd still be doing what I love. Also, if I were to have enough free time for a few college courses, the credits that I earn from HM technical training would count towards my degree. It's a win win situation. Roughly, how any credits per semester is realistically possible to attain while serving in the Navy?
7) How soon after your first deployment can you start talking college courses (whether it be online, through the professors aboard ship or by a nearby "military friendly" college)?

By the way, the number of years I serve is not a factor to me. I'm not looking to get out after I get my degree. Im just rolling with the punches (:

I'll be extremely grateful for any answers that I receive & I'm excited about hearing your opinions/knowledge. Especially if you have years of experience under your belt. Thanks a lot!

If it is your objective to become a MD, I wouldn't accept any rating that does not guarantee you will work in a medical field, even if you have to go to another branch of the military. What good would a tour of duty working in engine maintenance, for example, do to further your medical ambitions?