[DJRansome]

With a 55G you are better off limiting to three species. You want to end up with 1m:4f of each. The two Maylandia (Metriaclima) are not small and more aggressive than the others. Don't mix them in one tank.

The other three would work, but you would only have the one blue male.

Maybe the callainos and the white labs and saulosi?

 

[DJRansome]

15 fish is the proper level of overstocking for a 55G. Since you want 4 females for every male (to manage aggression and prevent crossbreeding) that dictates the 3 species.

If you want 4 species, consider a 75G that is 48" x 18".