I have pygmy sunfish (e.zonatum/evergladei/gilberti) , l.ommata, and het formosa together in one tank and all is well. The formosa are more aggressive feeding-wise, and a bit larger (around) than l.ommata.
I'd probably go with 6 pygmy sunfish and 8-10 ommata in a planted out 10g.
Unfortunately both males and females tend to look bland except for a dominant male or two, depending on how much tank space they have to work with. Let me know if you have any other ??s or need help sourcing some.