Since I updated to the newer v3.0.5 app, I retested and posted about that in the unofficial topic for that version. I now think the Devices tab disarray that I experienced after emptying a Group was a one-time glitch, because I’ve been unable to reproduce it. The other issue with non-empty Groups still having an “Empty” label still exists, but at least it eventually resolves and may not actually be classifiable as a “bug”.
I’ve updated my Wyze Ticket accordingly.