I'm putting this out there in case anyone is interested. You can have multiple playable characters under one single player save file. I'm not sure if you can do this on console, but you can basically create a local multiplayer save file that pretty much acts as single player game. This video is the most concise explanation I could find
Personally, I would recommend capping the custom characters you create to max three if you want some companion feedback. Each character takes up a space in your party that you can't remove (or at least I haven't figured out how to remove them just yet). The custom characters are completely playable and have their own separate approval system with companions based on their actions. This works for romances as well. Each character will have their own dream guardian interactions, so there are repeating scenes some nights. 100% would recommend this if you have multiple characters you want to play, but you just don't want to replay the game again.
