When you ask questions on message boards you get answers hopefully. If you don't like the answers then you are free to ingnore them.
However, most times the advice from experienced hobbyists is best heeded. Otherwise you might just as well go ahead and do what you want to do anyway.
You aren't going to like my advice either, I expect.
With a chocolat chip starfish, you obviously are not going to have a reef tank.
Starfish, although many do feed them, never needed feeding in any of my tanks. They lived off the detritus, algae, uneaten fish food that they encountered in the tanks.
For a 55 gal
tank your tank is already fully stocked.
My nineties only have five fish in each of them and you have that many in a 55? As the fish grow, you will probably have overloading of the biological filter, not to mention high stress levels of the fish that require more territory.
Adding a foxface now, after the tang is already there is really asking for trouble as the yellow will fight to defend what little territory he has.