I agree that multiple species Vieja can overwhelm that size tank.
A trio of the same species might work, if they were to grow up together from a juvie stage, combined with some large livebearer dithers that are found in the same geographic area.
Even a trio when mature would make a 150 look small.
I had good luck with a pair of V briedori in a 150, and their spawns.
and in another similar sized tank a trio of melanurum(AKA synspillum) and in another fenestratus.
some that have not worked well in such a small tank, were argentea, regani, zonatus, and maculacauda due to aggression, where the alpha just bumped every other cichlid (including same species) off. With these species, I usually ended up with one individual ruling the entire tank