Q: Match using new audio fingerprinting?

With very limited exceptions that I won't go into here, no one in these forums work for Apple.  We are  just users like yourself.  So, we do have any insight to answer your question.  You would have to ask Apple directly.

My understanding is that it is Apple Music that has switched to using the iTunes Match audio fingerprint model rather than identifying songs by tags. Existing mismatches such as clean vs. explicit, or failure to match with what is clearly the definitive version of a studio track are unlikely to be affected.

tt2

That I don't know, at least not for sure. I have iTunes Match but not Apple Music. I've mainly used iTunes Match to release my old iTunes DRM tracks for non-DRM versions and haven't trusted it with my main library.

If ratings and play counts are retained when you remove and then reimport your tracks then I don't think you're removing them fully from the iCloud Music Library before they are reimported. I have a Windows-only script called ExportImport that can be used to export metadata from one library and import it to another, but it would need combining with some additional code that I have in SyncStats since the replacement tracks would have different Library Persistent Track IDs. Date Added cannot be modified, but it should be possible in principle to save and restore just about any other metadata. Are you running Windows?

tt2