It's definitely not a flowerhorn. It looks like some kind of mbuna, but difficult to ID. As for the LFS, breeding pairs is correct in certain species, not mbuna though or any Lake Malawi cichlid (or Lake Victoria either for that matter). Mbuna are harem breeders (meaning one male and several females). It may come from the parent style of holding eggs/ fry in the mouth making the female unavailable for prolonged periods of time. The gravel they are referring to is probably crushed coral and it can help maintain a high pH but it's not required. Many of us use sand as a substrate and some use the crushed coral in the filter for the pH; others just strive to keep the pH stable in the upper 7s (which is what most city water comes out as anyway).
C. Afra "cobue", Labidochromis chisumulae, M. joanjohnsonae,
Ps. acei, Ps.cyaneorhabdos, I. spengerae
46 Bow front
Ps. saulosi, Labidochromis chisumulae