I have add-ons and they aren’t showing in either expansion. Draenor and Legion. Are there buckets in those expansions?
According to WowHead, the only candy bucket in Draenor is in your garrison.
The only two in The Broken Isles are in Dalaran: one in your faction inn and one in the Legerdemain Lounge, the neutral inn in the center of town.
This matches my recollection, although I didn’t go trick or treating very much this season.