Damp's contract is uber-valuable. His contract is similar to Nick Van Exel's in that you can trade for him in the offseason, and then his contract comes off the books. So trading for the cap space will not jeopardize the playoff push.
I think JJ + Chandler + Hill is too steep. But I would be inclined to make a similar trade, like JJ + Hill for Damp's corpse. Or JJ + Chandler for Damp's Corpse + Beaubois