Armor bonuses? I don't think so. Unless you're talking about a different bonus.
From the candies? I doubt Zen did that again. It was great but caused a riot. She hasn't done it with Christmas canes or St. Patrick's clovers so I bet these Halloween candies don't.
did anyone ask her? would be interesting to see if they do again.
all bonuses should stack imo.
these items are hard to obtain and extremely rare. if someone wants intake all their items at once to beat the highest lvl player in the game, he should have the opportunity to even if it's a big waste.