Your yellow Lab is a Mbuna. It's hard to say. My 150 has Peacocks, Tangs, Haps and Mbuna in it. If you do get Mbunas, get a few cause they seem to like to fight w/ each other. I have alot of Mbunas in my trank and they only seem to bother each other. the only ones I would be worried about are your Bricardis and Shell Dwellers w/ Mbunas. Zebras tend to be the most Aggressive in my opinion. (Red, Blue etc...) You might want to stay away from them. However once your Livinstoni Gets to be a good size he will eat all your little guys anyway. They are open water Predators and feed on fish when they mature. One day pellots next day your fish
I know, when he gets bigger he is going to be moved into another tank... right now he is still small. I am moving soon and I have delayed seting up a new one