If you have UpdraftPlus backup and restore and saved the plugins directory in the past you can then upload the old version of the WP User Avatar plugin. I just saved it a WP User Avatar2 and sent it to a compressed folder by right-clicking and it worked. I also named the subfolders wp-user-avatar2 in the hopes it will not say the plugin needs to be updated. So far it has not and auto-updates are not on.

Does anyone know if it is legal to put this old version on GitHub for people to download? WordPress is open source after all. The guy purchased the plugin but was really just buying that people had it downloaded. Everyone has the code. My version is not quite original as it does link to the user images on my site.

Also, is it legal to just create the old plugin in the WordPress plugins as it would no longer be a duplicate as the functionality has changed?

Really it would be nice for the old owner to do as they can tell he lots of people are upset. The big reason the new free version is not ok is that it slows down the sites that use it. Maybe they did not realize this would be a big issue for people.