I keep my Lightroom catalog in a Dropbox (Pro) shared folder but had too many problems with 2 different machines accidentally opening that catalog simultaneously. Doing so is like Ghostbusters crossing the streams... bad things.
I've not looked at Google photos too much, is there a good desktop (even if it's browser based) app for doing edits, facial recognition, EXIF data manipulation, Geotagging, etc?
Photos + shared Apple ID seems to be the only thing that is going to work.
Not entirely sure. Your requirements are very specific. You are probably in the realm of commercial software for professional photographers?