> You should be able to clear all the passwords out at once with a simple query in the database
Nope. I'm admin, but have no access to the the server, and would not risk running queries anyway, since I have very little experience in that. So I edited each course manually. Going back to do that for 15 minutes is a drop in the ocean compared to the gigantic, insane task I have ahead of me anyway.
And regarding my last comment about enrolment settings not being transferred when restoring. I tried it again and it worked.
No idea what the problem was the first time.