Are buff orpington roosters generally friendlier then others when they mature?
How do you chose the least aggressive at a feedstore, will the assertive one be over aggressive or do you choose the male chick that is hiding in the back because everyone else is tougher then him.
If you get two males and some pullets as 1 day old chicks will the males be more interested in protecting the flock from each other then trying to attack you every 2 minutes when they are adults?
I've known of good Orps and bad. Roosters are individuals. I have a Rhode Island Red rooster, and RIR have the reputation of being very aggressive, but I've never had a bit of trouble from mine. Your best bet would be to either get a rooster from a breeder where you can see the temperament of the parent stock, or you takes yer chances with day old chicks. If I were choosing at the feed store, I wouldn't want the "friendly" chick--I'd want one that was scared of you. When I've needed a rooster and wanted to get one as a chick, I've purchased four or six male chicks and then ate or sold the ones that I didn't like. I do understand that's hard to do when you don't have the luxury of space as I do.
You don't need multiple roosters to distract them from attacking you. Roosters don't have an inherent need to attack people. Most will tolerate you just fine, and if you have a rooster that attacks he should be culled. Aggression is genetic trait, so you shouldn't breed from an aggressive rooster. I would also not want a "friendly" rooster. I want one that's wary enough of me to move away when I walk toward him (this is also a sign of respect, that he knows I'm higher status than he is) but will not panic if I happen to brush up against him in the chicken coop. I have seen so many awful stories here on BYC of people that had pet roosters, loved them dearly, the rooster sat on their lap, or wanted to be picked up, and then sexual maturity hit and that rooster became a nightmare. They just didn't have any respect for the human and tried to dominate them.
Roosters can get along--they don't defend the flock from each other. I have three in my pasture right now, with 50 hens. They live in the same hen house, and roost on the same perches together. They were not raised together, and they were all introduced to each other as adults. The key is to have enough hens (10 per rooster is a common number) so that the roosters aren't competing for hens all the time. If you raise a group of chicks together, you have a very good chance of having roosters that tolerate each other as adults. They will fight a bit as they reach sexual maturity to establish their pecking order. Mine will fight about once a year, in the spring, when the lower roosters decide to see if they're strong enough to move up the ladder. Then the top rooster kicks their butts and the fighting is done for the year.
If you do decide to get multiple roosters, wait until they are at least 20 - 30 weeks old before deciding which to keep. You want to make sure they're starting to show adult behavior.