1. Yep, that's true.
2. Nope
3. Nope
4. Nope
5. Nope *
6. Nope
7. Only if you screw yourself.
Okay. The asterisk is placed there for a reason. While they cannot force you to do anything, they CAN call 911 and report that you're threatening to kill them and/or yourself and you might find yourself with a free ride to wherever it is the first responders take you.
Other than that, at 12:01am on the morning of your 18th birthday you are free to leave and never return.
(There is one other possibility - they rush to court to try and have you deemed incompetent and ask the court for help)

