Yes - This is a bit weird with the ‘autosave needs to be resaved but can’t’ problem after fixing redirect. I always fix redirect for the entire content folder. Then save all and ignore the ‘untitled’ needs to be saved message and restart the editor. After restart you should be able to delete the folders. You can also delete the folders in explorer if there are no redirectors left in it.
Also multiple renaming can cause problems. Always good to fix redirects and then restart when you have to rename something that was already renamed before.