Take the africans out til you get a bigger setup keep the Tiger Barbs add 8 more Tiger Barbs to make a full colony maybe add a small cories.
When you get a 55gal rock the tank out add about 18 small Mbuna in 3 sets of 6 fish
1 set of Yellow Labs total 6 fish
1 set of Acei total 6 fish
1 set of Rusty's total 6 fish
Stay away from auratus, chipokee, Johanni, Bumblebee's, Kenyi and Zebra's these will be your killers, the above stock list is aggressive but not as aggressive as the ones i told you to stay away from.
Once you become acquainted with Africans you can try the more aggressive species down the road.
As for Red Zebras and Yellow labs they can hybridize with each other..
Or you can go ahead and try those fish and see how much money you can throw away.. Good luck..