Jamie Garrett

So, it sounds like no, changing the name of the folders will not work. Minecraft will just creat new folders again.

This happens in normal worlds too and not only superflat. Also happened to the wandering trader, but since the llama are attached to him, you can still see where he should be and therefore trade with him. I noticed my villagers gone as well first and then saw that a wandering trader vanished. my world is peaceful so I know it wasnt because of zombies.