We had delicious crab rangoon one night at the WL club level lounge during the appetizer time block at the Wilderness Lodge a few months ago. It was really good and very fresh-big chunks of crab mixed into the cream cheese mixture! That is the only place in WDW I've seen crab rangoon.
I think I once came across a yummy crab egg roll, but I cannot recall which restaurant we were at-it was either Narcooses, CRT, or WC.