I wanted to say a few words to back you up on your choice to give him a good life with some sweet hens. If he's able to eat well, then he's doing what every chicken most loves to do, and of course he should have a good life.
No reason to even consider ending the life of a content chicken.
I think that any hen could get territorial, but that an older one or one lower in the pecking order will not be aggressive to him. Non-alpha silkies or bantam cochins would probably be the safest bet, although I have some quail & dun quail D'anvers who are passive as pie too. I don't know if you're close to Pgh, 9probably not) but if you are, I have a couple bantam cochin pullets to rehome to you if you'd like them for your feathered man.