Regarding the re-boot question, Joe: a few weeks back, I was both host and quiz-mistress on our weekly family quiz when my computer suddenly froze! No cursor, nothing! I had to crash shutdown and re-boot, which took ages, then get back into Zoom - another eternity, it seemed. But when I finally got back in, everyone else was still there: they had been having a great chat in my absence.
So, it seems the meeting only terminates if/when you "end meeting": you can leave and come back even if you are the host.