To answer your second and third questions: yes, and maybe. I was a political science major, and I was always asked why I chose political science as a major when I knew I wanted to be a doctor. Out of 7 interviews and probably 15 interviewers, I was only "grilled" on this issue twice. One student interviewer just couldnt seem to understand why I would choose political science when I've known for many years that I want to be a doctor. On the most part, however, I think the major was nuetral at worst and positive at best, as most people were interested in my choice, and naturally, how I feel politics and government has affected and will affect health care in the United States. If I can suggest one thing, it would be to make sure that you know a good deal about health policy before you enter your interviews. Most people will expect you to know a good deal about this based solely on your major, despite the fact that you may have never taken a single course on health policy throughout your undergrad years (I never did; I concentrated in Law, but that doesnt stop others from making assumptions 🙂) Good luck, feel free to ask more questions.
EDIT: To provide a little context for my comments - I start medical school this August; I was offered 10 interviews and received multiple acceptances, despite having a lower 😱 GPA than yours 👍