From what I understand and remember growing up, RIR roos are mean. I also hear that Ameracana roos can be mean. If I was going ONLY with the breeds you mention in the OP, I'd pick my roo to be a Buff Orpington. I know my BO pullet is sweet. The breed of the roo won't be too big a deal as long as he's big enough for the ladies and not so aggressive that he attacks you for collecting eggs. I hear that Cochins are sweet too, not sure about their eggs and quanity of eggs. A site I use to just look up egg color/quanity and purpose of the chicken is... http://www.ithaca.edu/staff/jhenderson/chooks/chooks.html
I'm sure it doesn't list all the breeds, but I like the way the chart is laid out.
I'm sure it doesn't list all the breeds, but I like the way the chart is laid out.