Do as much research as you can on Mbuna, that is always a plus. What size tank are you planning to put them in?
Using a crushed coral substrate will keep the pH high, do not mess with pH up or anything. Keeping the pH at a constant level is more important than keeping it high. Most fish can live in different pH as long as it's constant.
A ratio of 1 male to about 4 females is ideal, so he won't pick on one female and stress her out and kill her. I personally like the idea (my tank is this way) of having all males. I haven't had much aggression with an all male tank and the colors for the males just pop. I highly suggest having an all male tank and with it you would put one male of each species.
Plants aren't necessary for them, and most likely if they are real Mbuna will eat them, so really no point in having plants unless they are fake. I have heard they tend not to eat Anubias
(i think that's what they are called not a plant expert here).
What type of Mbunas are you looking at? If you have anymore questions feel free to ask.
OH AND I ALWAYS SUGGEST A FISHLESS CYCLE!!!