A lot of cichlid exporters have outdated/mislabeled names for fish. Things go by a certain name for a few decades and then they stick. Most Satanoperca are still labeled as Geophagus, just as many pet stores sell Geophagus surinamensis even though they're really G. altifrons or G. abalios most of the time.
Either way, they're all related: Geophagus, 'Geophagus' (the yet-to-be-formally-classified brasiliensis and sp. Red Bahia types), Satanoperca, Biotodoma, Acarichthys, Retroculus, Gymnogeophagus... and if we're going by cichlids that are equipped with gills designed for sifting/earth-eating behavior alone, that should also include Mikrogeophagus (the rams) and Apistogramma.
A little off-topic, but it's a wide world of cichlids out there and they're fun to get into.
As for the discus... tank-bred strains, unless you can trace them back to wilds, are probably hybrids. True wild discus from Lake Tefe (the greens) are classified as Symphysodon tarzoo. This works the same for severums. Several species in the Heros genus (H. efasciatus, H. notatus, H. appendiculatus, H. sp. 'rotkeil', H. sp. 'Inirida', and so on) will readily hybridize with one another, meaning that common green and gold severums seen in LFS can be any mix of those. We call them H. efasciatus in the hobby but it's unlikely they've been kept pure over the last several decades in the aquarium trade, especially considering that years ago they were probably all considered one single species.