I would like to migrate this person entity from YAML to the People GUI configuration, but I can’t figure out how to associate it with the existing user (who is part of the Owner group).
Haha, you’re trying it the other way around! I used to prefer YAML and Git too, but I eventually gave in. Given the strong push from the Home Assistant team towards the GUI, I decided to move everything to the GUI, hoping it would make maintenance easier and let me take advantage of automatic migrations and new features without the extra work.