Access photos only from select albums on all my devices
I guess I was halfway stuck between an older way of doing things (sync) and a newer (cloud). The older way still offers selecting individual albums (e.g. for the two faces) for syncing between two devices.

Photos apparently still makes lots of mistakes in assigning photos to albums (as is its want) and therefore the result is still less than optimal overall, but it is probably the right way for me to go.