Tim Hunt

Visibility of quiz grades is controlled by the quiz settings (in the Review options section).

I don't have anything do add to what I said before. The sensible way to handle this is withing the pre-flight check process - that is what it is there for in Moodle.

Just saying "But during this redirection, the proctoring instance (along with all the permissions and verified checks) is lost, " is not a sensible objectoins. During the process of a student attempting and submitting a quiz there are lots more very similar redirects. If the proctoring solutoin cannot handle the kinds of redirects that Moodle does, you have a much bigger problem than the time.

AA_QB_Def contains 10 questions were part of course AA.

When you clone the course, everything in it gets cloned, including the category and the quetions. (And, the category is not magically renamed.)

This is a different category - a safe way to test that is to rename the new category, and verify that the old one is unchanged.

So, yes, safe to delete.

Which Moodle version? latest Moodle version reassure students by showing the time the answers were last auto-saved. And, you can always set the time to faster than 2 minutes. (Open University currently has it set to 30 seconds - of course, if you are going to change it, monitor server load before and after.)

Yes, as Hugo says, these days, you probably want to create a TinyMCE plugin. And, you are in luck, Moodle Academy has just released a course about how to do that: https://moodle.academy/enrol/index.php?id=148

That includes this video: