you can't have a batfish in that tank. they get quite large. the 10 nassarius snails will starve to death unless you put food in the tank for them.
i would also leave the starfish out, because we don't know what it eats. the idea that it eats bacteria is non sense IMO
, and if it was true, you would be killing your tank adding it, because it would eat the bacteria that is necessary to sustain the rest of the livestock. if you are dead set on a starfish, i would suggest serpent/brittle stars. these eat uneaten food, and you can hand feed them. just stay away from the green brittle. the red ones are cool, as are the harlequin serpents.
also, i found this info-
which says they eat inverts. it's a predator.
you will need A LOT more water movement than a 75 gph
power head. perhaps a pair of 750 gph
power heads would be better.
i wouldn't even bother with the protein skimmer.
and lastly, i would use another 20 pounds of live rock.