Understanding different Chinese writing styles
Short answer to question one:
While you can still see them there, all of them are in use now, in different situations.

Short answer to question two:
In school, teachers give the one that they like, based on local policy or their textbook. Usually, one style is enough. 楷書 or 行書, neither is easy to learn, so different people work it around in their own style, a bit mixed of several styles, or new styles. Simple is good, when people write characters.

I'll edit this post with more detail if you want.