restore notes iCloud IMAP
Try restoring ~/Library/Containers/com.apple.Notes (I would keep a copy of the existing folder in case this causes other problems). That's where my Notes seem to be stored. If that doesn't work, you can dig out the individual files representing your Notes within that folder.

The directory structure of the com.apple.Notes folder is very odd. It seems to have aliases to things like my Desktop and Movies folders in it, for reasons that I completely do not understand. In any case, I found my IMAP Notes in ~Library/Containers/com.apple.Notes/Data/Library/CoreData/ExternalRecords/E7804A95-977C-4A1C-98A1-8C1D77E02D49/IMAPNote/_records/0/

Hope this helps!