Hello Doug, cool deal on the family harem N. Pulcher and they are basically the same as N. Brichardi but with alot more yellow coloration, for the magic of a harem to work is that you have to have a intruder in the mist so that they have something to defend against if there isn't any intruders they will focus on the next best thing which is an elder juvie offspring, i am assuming you have only the daff's in this tank with their offspring, if so to avoid the brutality that comes along with cichlid behavior and fry survival you may want to add some target fish, with my 120gal i have frontosa's and brichardi's my adult brichardi's chase off the frontosa's with great attitude, and for a 4 inch fish to chase off a 7inch fish with ease is sorta comical in all, now i am not saying go out and buy frontosa i am saying you may have to add target fish that can withstand the aggression of daff's, this could be a group of 3 N. Lelupi or a pair of Julidochromis sp. or even synodontis or a combo of one species from all three, but as long as the parents and elder juvie daff's they will focus on them as a threat and they will unify as a whole and defend the colony, to off set the options you could go with a fivesome of aust. rainbowfish as target species as well they are fast and mostly occupy the top water section seldom do they come down to the bottom when they know a predator could be lurking, happy hunting my friend..
Also take a look at my avatar this is a photo i took a few months ago clearly the frontosa dwarf's my brichardi male which chases him away when too close to the nest. this photo was shot when they were cruising near the top of my tank, which is an everyone zone..