The crab legs are available at Cape May, just not all you can eat. You order them by the pound.
Check the menu at BlueZoo. You may find them there. I've only been once, and can't remember if they had them or not. I know they have lobster.
Fulton's is not my first choice for seafood. They've fallen off in quality in the past year or so and until they manage to 'get it back' I'll not be dining there.
There are two crab places very close to WDW property (just beyond Crossroads) if you feel like going off site.