Crafting the Halloween Items
Yes I believe all the items you can make are tradeable. As for the Jeweler recipes, I believe you can buy the recipes from the Candy Corn vendors near the crafting tables in Lion’s Arch.
I didn’t find any jeweler recipes from vendors, only artificer for tonics and chef food recipes, there is also 3 item-intensive recipes for huntsman, artificer and armorsmith from the mystic forge which will let you craft permanent versions of the bow, staff and shield sold temporarily by the vendor and a sigil of the night/mad king recipe from mf aswell…thats about it for recipes that I know of