I agree with Jon, it might very well be a four armed version of this:
Image from
Here
If so, it will absolutely positively die...if not from osmotic shock, then from being in a new tank, or from starvation. Most likely it will die within a month from introduction....if not, a few months down the road. These stars can not be spot fed, belong in a very mature tank (no less than 6 months), need a 4+hour acclimation and tend to do poorly except in much larger tanks. There is always a chance, I guess, but the odds are not in your (or the starfish's) favor.
Ditto for the anemone.
What sort of lighting do you have?
FWIW, you have WAY too much stuff in your tank and you are rushing things. This skips over the most basic rule of keeping saltwater tanks: be patient. Without patience, you will kill a lot of stuff....forget about wasting money....you will KILL a lot of stuff. We all learned that, but for many it was before resources like this board became available.
I really urge you to do a lot more research, and don't buy anything more until you ask on this board. Certainly do not buy more animals! I know it can be tough, but believe me, people here will help!
If you can post your exact water parameters, that would help out with knowing where your tank is at for its age!!