A 40 gallon breeder is just big enough for one mid-sized sunfish, such as a redbreast, longear, warmouth, or rock bass. A bluegill or redear needs more space than that. If you want to keep more than one sunfish in that tank, you can go with any of the Enneacanthus species (banded, blackbanded, bluespotted). These all occur in Florida and are compatible with most 'community' natives such as minnows, killifish, and darters, but will still eat small feeders such as juvenile guppies.
There are some small Lepomis species such as orangespotted and bantam sunfish which could be kept in a group in that tank; they don't occur in FL but are occasionally available from online vendors. Pirate perch are another option.
I don't recommend keeping sunfish in pairs. You'll end up with one dominant fish who harasses the lower-ranked individual constantly. If you get a 75 gallon you could keep 3-5 mid-sized sunfish, which is a more tenable group.