These would probably be one of the best given their size and temperament. They could hold their own. Of course sveni are one of the nicest in terms of color but their adult size is much smaller and I don’t know how Cichla would treat them.
The other options for large geos are abalios which mostly will look like these, or winemilleri. You could also do brasiliensis which are showy, large, and aggressive, but technically not a surinamensoid-type.