Around the DC area, the cichlids in these tanks are generally not hybrids, however, they tend to be a nasty little bunch. Typically, kenyis, auratus, bumblebees, EB johannis rustys. They are hardy for the beginner, but all have issues in a community imo. Kenyis get nasty and breed with everything, auratus and johannis are incredibly nasty, bumblebees get 8" long and mean and rustys, well, they're a little less aggressive, but in the same boat.
Unfortunately, no one at Petco tells you this and you end up with a bunch of nasty hyper-dominant mbuna interbreeding in your Malawi tank.
As the other posts said, do the research and pick specific fish for your tank. Do you want to do haps/peacocks, big predator haps, mbuna? Generally, start with a plan and stick with the plan to avoid compatibility issues in a Malawi tank.
Good luck and don't let these replies turn you away from Arficans. Find a good LFS and if they don't have what you're looking for, they can probably order it for you.