They are one of the milder dottybacks, slightly more aggressive than a fridmani but not much more. I've kept them in harems (when i bred them i didnt see much of the male, so it was nice to have the females) and your plan of 3 small ones added together is the way to go. I didn't find them that limiting with regards to tank mates but fish that like to swim around the rockwork, like gramma, or wrasse, would be the most likely targets. I had one square up to a new halichoeres wrasse but there was never anything more than that.
You tank has enough space that I don't think they would be much of a problem unless you added really timid fish like firefish.
