I'd probably hold off on the starfish though, I've found them hard to take care of and if you get a sand sifting one they can easily strave under the sandbed and decompose. :-(
i also think 2-3 would be fine on the chromis. Your other stock on the list isnt very large so it should all fit. But then you most likely can't add anymore than what you've listed.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.