have a CB splendid that is a perfect gentleman in with a gramma and black cap (I know they are different fish but similar niches - might want to think about that instead of multiple Dotties
And in my tanks, I find tang stocking and aggression can be positively affected by hiding spots and multiple swim lanes supported by powerhead induced flow
I introduced two captive bred orchid dottybacks and they actually paired up and had eggs on the regular. Might have been lucky, but I've heard others having the same luck as well.