Poster,
I can’t answer all your questions, but I do know a (very) little.
The insurance that people must buy is not government insurance. There was an option for people 55 and older to buy Medicare, but that provision was deleted.
Currently, the proposed fine for people not buying insurance is $750/year. For most people that is cheaper than buying insurance. So for a young, healthy person, it pays not to buy insurance and pay the fine instead.
If that uninsured person gets sick, he can then buy insurance, and since the insurance companies are not allowed to turn anybody away for pre-existing conditions, he’s guaranteed to get insurance.
Since the insurance companies are going to be insuring a lot more people, many of whom have pre-existing conditions, the premiums for everybody are going to go up.
I know this just barely scratches the surface of the 2000+ page bill the Senate just passed, but I hope it helps.