IMO, if you want a long term Mbuna tank this is what I would do...
Lots of rocks. River rock, lace rock, Holey Rock, even Pagoda Rock (because it stacks really well). Make high stacks of rocks, too.
The rocks have an awful lot to do with the success of your tank...including, but not solely, being a great source of food when algae starts to grow on them.
I would start with juveniles.
Starting up a tank with all very young fish makes them get along better than starting with all adults...or half adults and half juvies.
Do not get "like colors"...
If you get a pair or a trio of Kenyi then getting an other "yellow" colored or "blue" colored fish can be bad for the tank, as similar colored fish will sometimes go at each other.
A nice starter tank, IMO, would include a group of juvenile Demasoni, Yellow Labs and a nice OB, for instance a Labeotropheus or Fulleborni (sp?) group. At least six of each would do the trick.
Just my 2 cents.