\\\\demasoni are both blue too. 55gal is not really big enough for more than 2 species of mbuna. I would go with the lab/dem mix, as said above. 6/7 labs and 12/15 dems. If your water perams are right without buffering, then try to get black substrate, it will really bring out the colours of this stunning combination. If you need to buffer your water, then use coral sand in your filter.
Yes, you are right. I was thinking of Johani.