Here is the way I think Apple Music/iCloud Music Library should integrate with your owned local music iTunes Library.
Of course this is simplistic and there are likely obvios issues not accounted for. Feel free to add (as if you need me to say this).
- Local music in iTunes/iDevice should never be edited by iCloud Music Library unless it is a Match download
- When downloading a Playlist any local music (sans Match) should be directly synced
- When on another WiFi or cell local songs (of course) can’t download
- If local music unavailable then iCloud Music Library version could be downloaded
- Local music should have an identifier mark (similar to the download icon in the top right)
- Local music in iTunes/iDevice should never be edited by iCloud Music Library unless it is a Match download
Of course this is simplistic and there are likely obvios issues not accounted for. Feel free to add (as if you need me to say this).