Then you are going for the right type of tank
You can combine them... just use the basic principle of not combining the same genus and try to stay away from similar looking fish.
pseudotrophues saulosi *
yellow labs *
Pseudotropheus sp. "Acei" *
Pseudotropheus demasoni
Metriaclima estherae
Iodotropheus sprengerae *
Tropheops sp. Albino or "pombo rocks" .. I sold some of these to someone in the club... had quite a few fry. Great yellow color on the females.... not sure if they still have them or not though.
These are all fish with colorfull females... at least a little bit of color... more than your average female from malawi.
All are available around here as well.
Personally I would pick 3 from these.... and add at least 6 of each. Remeber don't combine 2 Pseudotropheus and you shouldn't have any X-bredding provided you have females of all species. Although I really doubt that a demasoni would cross with any on this list. But I can't guarantee it as I haven't tried it.
Before I kept Tangs... I kept Malawi
The ones with stars by their names aren't as aggressive as most Mbuna.