Ok, I'm pretty versed in cichlids (aftrican and american).

The first problem, the afrcians will kill ALL of those w/o question b/c of territory. How big is the tank?

Africans are very aggressive, but don't get huge. If you decide to add more (assuming the tank is atleast 20 gallons) do so immediately, and move everything around in the tank. Also, make sure you have more caves / placed to hide than you have fish.

Central and S. American cichlids are even MORE aggressive, but it usually doesnt show until they outgrow the Africans.

American cichlids (angel fish) will destroy any common fish if you get aggressive ones.....and will grow to a decent size. I had 1 angel that reached 10 inches top to bottom.