I am so happy you have your eye on Drako! And yes I figured that out about the mare as soon as I posted her and knew you probably wouldn't like her, but it's okay!
He was homebred, but his pedigree behind his sire and dam have all been wild mustangs, but we have had Drako ever since he was just out of his mother.
He does not have any aggression towards other horses, but shies away if horses show aggression. He is the normally the leader, but will not fight for the spot, but if put in with mares, he will take his favorites and be around them grazing and keeping the straight. Like I said he has probably changed over the years as he was 5 when we figured the problem out. And as long as your horses don't normally show too much aggression (rearing and biting/kicking), he should be alright with them.
Yes he can learn certain things but the only problem is you must speak loud and clear. We have taught him some commands already when he was younger, and may recognize them if you teach him some. He is pretty much a fast learner and would be right by her side until commands are given.