It doesn’t seem like it would matter what you name a OneNote notebook, but I’ve found that it does. It seems that whatever you name a notebook, it will create a folder in Documents in your OneDrive. You won’t see it locally, but it’s there just the same. You can see it if go to your OneDrive online.
Why does this matter? Try creating a folder in OneDrive named Aardvark if you already have a OneNote notebook named Aardvark and you’ll get an error. I haven’t tested the reverse.
It may be best to adopt a unique naming convention for OneNote notebooks. Aardvark Notebook or Aardvark Notes, etc.
I’m not sure if it’s possible but I would prefer it if MS wrote the OneNote files to their own separate directory on OneDrive. I’m going to explore that, so if someone’s already been there, it would be helpful.