Sounds like he's doing better-- so he's back in the main tank in a box? I assume there's a cover, and it looks like you drilled some holes for water flow. Better idea than the bucket now that he's revived. I'd still do a divider eventually, it may sound funny but even in the main tank a box can slow his growth.
Looks male to me. As far as being accepted by the other fish, based on their behavior I still say do a see through divider, give it time, and see if eventually they ignore him or accept his presence. It can definitely work, I've done it, but it's not guaranteed.
Other options: 1) keep him divided until he's too big for the other fish to mess with. 2) Get him his own tank.
Will he ever get along with the female? Maybe yes. Maybe no. Or after he grows he could turn into the bully, or even kill the female. Cichlids aren't always predictable.