The choco chip and the angel will be fine together... Generally you don't want choco chip star in a reef setup, as they will eat clams, some corals, and many other things you don't want them to touch.
Sonny
actually, starfish are very sensitive to changes in salinity; if your tank salinity has a noticeable difference from where you got the choco from, it could actually deteriate in the tank; may notice that it begins to lose it's "chips"
Actually the chocolate chip has been in the tank for close to a year, just concerned about the angle picking at it someone said they are like a cleaner fish? besides that the star looks good
