do you plan on breeding the JDs? if so, yob might want to consider just letting them have the tank to themselves, plus maybe some dither fish . . . if you want larger tankmates, just be sure it's something tough enough to take care of itself, but not so tough that it threatens the JDs
some additions I would consider: 3-4 Rainbow cichlids, pair of Firemouths, single male Convict, single male Carpintis, single male Salvini