Basically. But nippy fish are a threat to the lionfish fins and the eyes of the shark. Also remember that not all seastars will be suitable for your tank....no Blue stars (or any "reef safe" Linckia, Fromia or similar), no sand sifter stars. Only non reef safe stars such as chocolate chip stars, general or red African are suitable. And the tank conditions should still be very good (especially specific gravity 1.025-1.026). Anyway, it is always a trick mixing aggressives with reef fish and invertebrates.
If you are not familiar with them, do look up Miniatus groupers, which have beautiful red coloration and do not get huge (about 18"). IMO suitable for the tank if you were sticking with larger (eg tangs, etc) fish. Definitely one of my favorite fish and often overlooked.