Frontosa fry will be ok in there for a while but it is likely to be too small for them long term.
I've got a few tang community tanks around that size that work well. The set ups below might give you some ideas.
4x2 - Lamprologus similis, Firefin comps, Cyp kitumba
4x2 - Alto fasciatura, Xeno spilopterus mbilibili, brevis, gold occies
5x2 - Gold comps, caudopunctatus, leleupi, Juli ornatus, Lepido hecqui, a bachelor group of Cyp kigoma, Cyp mpimbwe, Cyp kitumba, a few frontosa fry
Have fun setting the tank up!