Can someone point me to an up-to-date, comprehensive primer on how Item Bank sharing works for New Quizzes?

It seems there have been so many updates that I'm not sure where it currently stands.

If not, my main questions:

1. Can item banks be associated with a sub-account at this point?

2. When item banks are "Shared with a course," and then that course is course-copied, does the sharing come along with it?

3. What is the current situation related to Outcomes and Banks? I know this is has been problematic but I can't remember why. Does sharing factor into this somehow