This sounds like a fun project to be honest. Are there any risks involved by getting bad content through federation that’s out of your control?
Just a week or so ago I read an article about a guy running a tor exit node personally and being held responsible for the traffic
I’ve had this issue in the past. I had to spend hours on the phone with apple support to get them to manually remove my number from the iMessage database of known numbers. Then you also have to wait for that to sync back to everyone’s devices who has you as a contact. It was awful and still didn’t fix it 100%