1. No
2. Yes. And while you do get some resources from breaking spawners I generally find it best to avoid destroying them as they make good farming spots.
3. Far as I've seen only mushrooms respawn inside dungeons. Nothing else does.
4. Yes farming plants is a thing, you will need a forge to start though.
5. Yes. Start a boar farm, its a good source of meat and leather. You can also tame some creatures besides boar.
6. No.
7. Yes
8. Yes. Looks to be 5% skill loss on death, but you get a temporary buff on respawn to prevent further skill loss.

Only tips I have for you is keep well fed, setup outposts, and take materials for a portal when traveling far from home.