I don't see them being as aggressive as Amphs, but I would say that they don't belong with moderately peaceful SA fish. I had Red Bahias that were pushy with much larger severums and Geos when they were only 3 - 4" fish, so eventually I rehomed them.
I would not keep two together in a 75. Chances are you'll have conspecific aggression issues with them unless you end up with a pair, and at that point I'd be concerned with the other fish in the tank. One thing about the brasiliensis complex is that they will spawn very young and small. I had fry from 2.5" females that were only about 6 months old.