Re: Premiere Pro does not appear to be nondestructive

So you're basically using the original file as a status check for bad data.

Premiere will do .XMP sidecar files on some footage like P2 or RED files, I believe, but it isn't an "always the case" setting.

Alternately, if you turn those original two settings off, then you can still add metadata-like information to each clip that lives exclusively in the Premiere project file. If you're a lone wolf, it could be sufficient, but if data is going to multiple people, I would still lean towards an embedded metadata solution.