@CatSnip404 do you have any pictures of Nero that you could share?
My Simone does, but she has arthritis due to old age.
Have another issue that may or may not relate to the FIV + status for Orville. It seemed to start yesterday, but when he is touched on his hip he turns as if to bite (but doesn't). It's not the sensitive lower back area, but on his hip about halfway down. I know no one here can actually diagnose this, but does anyone have a cat who flinches/turns when touched on the hip? I know he has had injuries in his life outside, including one where he couldn't put his paw down, but that was the front leg.
And Henryetta is still hissing at him but I think it is improving. She eats next to him and will let him sit in the window with her (very close to her) but it is all on her terms. Orville is trying to become the Alpha cat by running Chaucer off the comfortable places to sleep. Chaucer sometimes challenges and sometimes just jumps down. I don't like this.