The main limitaion will be compatibility and size( I'd expect the livingtoni to get huge like a venustus so 125gallon tank), if some of the others can handle the mbuna, a general cichlid flake as a staple should sustain all well with, suplement foods can be easier directed at fish. Try an eyedropper. But frozen krill to suplement the carnivores, is a good idea, and if the herbivores and insectivores get at it a little nothing to worry about it's healthy in small amounts for them as well, same with veggies and spirulina suplements. Simply feed a well rounded staple with meatier suplements directed at the carnivores and the plant supplements directed at the herbivores, I wouldn't do anything special for the insectivores let them get at whatever they want