Yes, the other male would still come. How are you sure he would've gotten killed? If there's too much of a power imbalance, then maybe keep him in the coop for longer
Yours seems like a really nice guy. I'd wait one to two weeks before letting them free range, you should also see every girl get mounted at least once, because if he isn't interested in her, it's more likely she'll find other company
OK. The deal here is whether your girls accept your guy. If they'd rather be with the other male then you've got a problem. I'm inclined to believe that his girls don't accept his guy, otherwise he wouldn't be coming over so often. That said however, he is a chockerel so it's not completely...
If one of the boys isn't willing to drop the fight, then there's not much you can do there. You should make your yard secure enough that the outsider can't get in