Good suggestions so far
Another idea would be to do a single EBA and then some smaller cichlids like Bolivian rams. Since you said you wanted some diversity. Could do something like 1x Acara, 2x Bolivian rams (pair, or some people keep them in small groups of 1M x 2-3F with success) , then some tetras to act as dithers, maybe some corydoras catfish to clean the bottom. The bolivian rams could be substituted for pretty much any apistogramma or mikrogeophagus cichlid, as long as your Acara isn't particularly mean it should work.
I would also ask what your water is like, these south american cichlids prefer softer water with lower pH.
If your water is harder with a higher pH, Amatitlania nanoluteus would be a cool fish to keep and would be OK for your tank size in a small group. Could keep some livebearers like swordtails with them for a realistic central american themed setup.
