Sunshine Peacock, eh?
Well, that's another Malawi rift lake cichlid - he should probably be returned to the LFS with the Kenyi (or, you could set up a second Malawi tank with sand, rocks, and more fish), or you should return the Convict, Firemouth, and Jack Dempsey and keep the two Malawians.
If you build a Malawi rift lake tank, you've got lots of options - just do online searches for different kinds, make sure you build plenty of caves into your rock structure, and you've got a lot of options in a 90 gallon (someone with more experience can fill in the gaps here better). Google it to get an idea (and look up Yellow Labs, Blue Zebras, Mbuna, etc).
If you keep the 3 SA cichlids, you could probably add another convict and another firemouth, and maybe one other large, aggressive SA/CA cichlid, but that's probably getting a little crowded. Again, others with more experience can give more guidance here.