addRef, yes in the sense that it will not crash anymore, but it's still problematic, like what if the query is really slow and the player trades the item and then we remove the item from the player who received it in trade because it's the same pointer?

isRemoved, no, once cleanup() is called it's removed to the point where it's no longer safe (unless the refcount is above 0 which you can guarantee with addRef, and in which case you won't need to check isRemoved because you know it won't be free'd if it hasn't reached 0).