Well i did some more research and thght mayb some gobies and blennies like green mandarin gobies, scooter blenny, red lizard blenny, orange spotted goby, bi color blenny.
That thing you posted is both a hang on filter and skimmer. For a FOWLR, that would work fine, but I think that if you are going to do a full reef I would get a dedicated protein skimmer.
now that you choose your type of tank your going to have to revise it a bit in a 30 gallon you can't keep that many gobies and blennies together they will fight with the different species but your getting on the right track.