In CA you are a minor until 18
Yes they can.
both
sole custody
No
Only if the sixteen year old is emancipated.
"16- and 17-year-old applicants" OR "sixteen- and seventeen-year-old applicants"
None without a court order. see link
Can à 17 year old move out
Yes it's perfectly legal.
NO
Yes, but only if the legal parents sign all rights.
Yes, it should be hyphenated like so: sixteen-year-old boys.