Yeah it was a little troublesome at first, the kenyii have been incredibly docile, the yellow lab can be a pain sometimes. The biggest issue I had were the Oscar and the Mayan. Once I got some more rocks in there and driftwood they have all gotten along, no nipping of fighting at all.Welcome aboard
That's true about ph but you also have to consider the aggression level of Cichlid species.
Best of luck to you, that mayan is a beautiful fish, but once fully grown they can be a real handful. Would probably keep an eye on it as it gets bigger.