Your best sources for information are people who've raised roosters indoors with a hen successfully. I've only kept roosters with hens or hens without roosters and never as inside pets so the only thing I can advise you on is how different a rooster acts around a hen and the other way...
Because you're attached to this fella I say give it a go but be advised crow collars suck. Not only do you have to be very careful what you feed him if you put it on too tight he can die