Well, It Must Have Worked
The site has been updated and most things seem to work despite a couple of serious mistakes on my part that could have resulted in a lot of extra work that I don’t really need at the moment.
Fortunately I have things backed up, but trying to find them is not always simple. I’ll know better the next time and be better prepared for the recovery, as it took about an hour before I was sure that I still had a site that I could access.