I would not go with the sharks - then again, I've had this argument time and time again with people about how having to remove a fish from your tank because it's gotten big causes unneeded stress on the fish, on you, and on your tank in general (sometimes catching the little buggers requires a lot more tearing apart your tank than you'd like)
Personally I'd stick with a fish that you can keep for the long haul. I love sharks, they're beautiful, elegant, and awesome to watch - but they also have very specific needs. Don't become one of the idiots on youtube posting a shark WAY too big for the tank that it's in.
Not passing judgement, just making the suggestion. It takes a very special kind of care to keep a shark in an environment in which it will thrive. While 180/300 may be the minimum requireds for the sharks you mentioned, I personally believe they shouldn't be housed in anything that small either.
firefish, ocellaris clown fish
caulastrea, green star polyps, palythoa, zoas