Hi, Tim. Turns out you're partially correct!
The new screenshot shows that options on the bottom, which don't include anything like what you suggested. However, the edit menu does have a "restore" option. Unfortunately, once again, this is one of those solutions that requires actions on each individual question rather than the full selection. Works OK in a small quiz, but our 100 question exams are going to take a while.
The thing I don't quite understand is that even though these questions are marked as hidden, it has NO negative effect that I can tell on the quiz in which they are used. So, it seems that technically I would not even need to do this step. But I'm a bit OCD about it and I also want to understand it.
Thanks for pointing me in the right direction, though!! As always, I appreciate your help.