It is certainly possible to mix species from all over the world in a tank, however I wouldn't personally try it in this size of a tank. Maybe if you stick with only the more "peaceful" mbuna, such as lab. Perlmutt, etc. it will work. But 54 corner, I would consider only just large enough to do mbuna on their own, I wouldn't go and mix a bunch of fragile fish with them. And fish like gouramis with trailing fins are not a great mix for mbuna, as they nip the long extensions.
Best of luck to you, though I think it's a bit ill-advised in this size tank. I would only get the most passive of mbuna you can find.