i also say pick one school. the bosemanis would be awesome to watch in a larger school, and you'll see great colors.
pick two species from this list and get larger schools. keep in mind that the barbs will stock the tank, so it would be best to skip them. if you choose the rainbowfish, then you will have to keep the other numbers low or stick with 6.
pick one of these for top dwellers, except for tyhe dwarf gouramis. get one of those. know that you can mix and match guppies.10 ZEBRA DANIOS 4 NEON BLUE DWARF GOURAMI 6 RED FIRE GUPPIES 6 GREEN COBRA GUPPIES 6 BLUE COBRA GUPPIES
12 DENISON BARBS 6 BOESEMANI RAINBOW 10 HARLEQUIN RASBORA 20 CARDINAL TETRAS 20 NEON TETRAS 10 BLACK SKIRT TETRA 10 X RAY PRISTELLA TETRAS
pick two species from this list and get larger schools. keep in mind that the barbs will stock the tank, so it would be best to skip them. if you choose the rainbowfish, then you will have to keep the other numbers low or stick with 6.
the corydoras are fine as-is, but pick either the SAE's or the otos.
6 FALSE JULII CORY CAT 5 SIAMESE ALGAE EATER 10 OTOCINCLUS CATFISH