Also, should there really be a keys-exist error for author and author_list if the entry has editor (or editor_list I suppose)? I have a couple of documents that are just collections of articles and don't have an author as such.

Agreed that the rename would be nice!

Also, should there really be a keys-exist error for author and author_list if the entry has editor (or editor_list I suppose)? I have a couple of documents that are just collections of articles and don't have an author as such.

The keys-exist check is intentionally pretty dumb because it's a very general "tell me if these documents have this key" thing. I would argue that at least for now, it's good to warn about author and author_list because the rest of the code doesn't really know how to handle things like editor (which are effectively aliases for author in many situations).

There's also a biblatex-required-keys check that's a bit smarter about what keys are required for what type of document. Maybe we can make that the default instead of keys-exist?