Are "Favorites" and edits synced with Photos for Mac/iOS?
According to this Support article from 2016 the answer depends on how you sync:
- If you import photos from an iOS device to Photos over USB, the favorite status will not sync (!)
- If you use iCloud Photo Library to sync across devices the favorite status will sync.
Source: Apple Support - Q: iOS Photos to OSX Photos favorites sync
FWIW this is totally offensive and horrible, I can hardly believe it. I just did an import of 3k images and apparently have lost all of my favorite statuses. What a mess.