For those of you with some questions, I just called the Columbia Office and asked a bunch.
Q: Do post-bac's who worked before starting pre-med need to fill out the "school interrupted question?"
A:No, the question is only for people who left school before receiving their bachelor's degree.
Q: Does the question "About how many hours per week, if any, did you spend in work for which you were recompensed during the college year" apply only to work in the past year, or any of your years in college?
A: No, it only applies to the past year.
Q: What should I list for my GPAs if I'm a post-bac?
A: Just list your AMCAS GPAs, if you haven't been verified yet just enter 0.00 for both.
Q: If I've attended the same school, once for undergraduate and again for post-bac work, how do I list it in the schools attended section?
A: It doesn't really matter, either list them together with one date range or twice with the two different set of dates, or don't list them at all if they're on your AMCAS primary.