You've got quite a few species you could put in a 100 gal, though you are somewhat limited with having the m.auratus in. Before I make suggestions though, is there any change you could post a pic of the yellow hap so we can id? How old are the auratus, and have they shown any aggression?
Then we'll also need to know what direction you want to go, more haps or mbuna, and what species can you source locally?
Sorry the yellows are Labidochromis Caeruleus and no havent seen any aggression from the m.auratus They just play around the rocks .
The aratus must be young yet, huh? If you want others you may have to rehome the auratus. Or if they start changing colors, i.e. turning brown, get rid of the ones that turn brownish and keep the yellowish ones. the browns are the males. you could see if that works to help minimize aggression. If not, prepare to rehome them if you want other species.
*well i suppose there could be enough room in the tank that there are no squabbles yet. I imagine that could change as fish are added. *nevermind about the age...just saw they're 3 years

No need to blush the auratus was a rescue misson Ive only had them a week I dont think they are very old they are about 2 ins. Pat