1) My wife incurreed less than 150k total, most of it in med school, not undergrad. Its really not that difficult to get most of your undergrad paid for, if you aren't capable of this it means you put no effort into finding grants. There are litterally even grants for people who's parents make too much fucking money, so there is NO excuse for you to exit undergrad with massive debt other than your own
I am currently in medical school, and am looking at about the same amount of debt (all medical school, undergrad paid off already). That being said, I go to a state school (plus started with some savings, plus have some parental support). The amount of financial support each state gives to their schools varies greatly depending on the state though. Grants are uncommon (since everyone expects doctors will become rich) unless you you meet special criteria -- impoverished background, under-represented minority, or are affiliation with a cultural/ethnic/religious group backed by private donors (also heard of a few set-up by patient advocacy groups and rural communities).
Private schools can be stupidly expensive (some run 70k+ a year), I wouldn't go to one unless my family was rich.
3) Doctors get paid for residency, they don't pay someone else for the privledge of doing it. They are working at that point, just watched closer (though less than they should be!)
Around here I think you can expect 35-50k a year, depending on what program you're in. While this isn't too bad for a family medicine residency that goes 3 years, others can go as much as 7-8 years (but you'll be earning more afterwards).
4) Bullshit. The cost compared to income is fucking trivial. You can pretend its bad, but my car insurance is more than my wife's malpractice costs, so again trivial compared to income. If you're doctor is paying high malpractice rates then you're intelligent move would be to find a new doctor cause yours has been sued one too many times, which indicates a pattern you might not want to be part of.
An Ob-Gyn's typical malpractice premium is easily more than a family doc's entire yearly salary. An average general surgeon can expected to be sued every five years. The cost and risk of malpractice varies greatly across specialties; your wife is probably in one of the "safe" specialties (Family practice, Peds, Psych, Derm, a couple of others), or has her malpractice subsidized.