Yep, that's why most fish and all crustaceans are a no for cuttlefish tanks. Seeing a cuttlefish hunt in person would be truly magnificent(I have only seen videos of this)!
AM had bunch of blue chromis, clowns, yes, a few wrasses (I think), some yellow bellied damsels, lots of zoas and... Can't seem to recall anything else but I'm sure there are more.
Would like to say that this is definitely a good setup. It is also aesthetic in design, very nice to look at. I think maybe a mushroom coral or something first. Then if it survives, then I suggest... well... Im not really sure. Perhaps the other members can suggest.
For curiosity's sake, what did you do with the crab? Cook it or flush it?