IMHO I'd just stick with 4 species, while overcrowding is good for aggression, there is a fine line between overcrowding and overloading your tank/filter(s) capacity.
Since p.socolofi are blue, I'd drop the m.callainos. And yes, other than the labs and rusties, you'll want 1 only 1 male.
Since p.socolofi are blue, I'd drop the m.callainos. And yes, other than the labs and rusties, you'll want 1 only 1 male.