itsjpb You're on the right track.
Except that
itsjpb old image deleted gone, new image jumps to front of library
Old image stays, new image doesn't match the original photo's recency, so it pops up as the most recent photo.
itsjpb edited image does not appear in camera's gallery preview
Correct.
itsjpb exif data changes (the primary concern)
I'm not particularly concerned about EXIF metadata, although it's something worth noting now that you mentioned it. My main concern is that I avoid editing images since the recency is inaccurate with the edited photo and doesn't appear in the Camera app, making finding photos really difficult. Although I wonder if changing the image name from Files would have an effect considering images are named by date and time?