it really sounds as if he were treated like an object before and now has a family. Sometimes with the ferals/abandoneds I've tamed too much attention is overwhelming. Maybe he would like to spend nights alone in the area most like a basement you have with a few toys he could roll if he felt like it.

If he chases the other cats back, it is probably already a form of play... and the feeding issue may be showing who is "boss" cat. Maybe give him some dry food in his night area? That way if they others are keeping him from eating he will have safe food and when you let him out to be social, they will sneak in and steal his food... learning to change places and be together can take time.

Hard as it is right now, it sounds to me like you are the best thing that happened to that cat... Two of my present cats howl when stressed or bored until I or one of the other animals wakes up and does whatever it is they want...Which varies from play to fresh water/food (not that it is gone, mind you, just not quite set the way they wanted) to someone to groom with.

Many of my cats met as adults and things have always---eventually---worked out.

good luck! and don't doubt yourself.... the cat probably isn't sure what he wants....