Unfortunately since even a single female of any species in a prediominantly male tank will cause great havoc, you kind of have to go one way or the other. All Malawi fish can interbreed. The mbuna seem to be very good at that. Even if you plan on never saving any fry from such a tank, the social dynamics will be a disaster. The most domiant males (reguardless of species) will spawn with whatever females are available and ready. With labs and acei being some of the least dominant fish in your mix, the females will be trowing hybrid fry left and right. Not to mention the male labs and acei being being regularly escorted to the back of the line by the more aggressive greshakei and zebra males.