It's a bit late, but I'm hoping this info can still help some. I finally figured out what I was doing wrong trying to get my items. You must equip, or not equip the items your given to get more. If you want Pumpkinhead I or II, or Trick staff I or II make sure you have no halloween gear equipped in your head or weapon slots. If you're wearing Pumpkinhead II, you will never recieve the first one. Instead you'll be given Horror Head II. What you want to wear is as follows...
To get:
Treat staff, wear the trick staff Treat staff II, wear Trick staff II Horror Head, wear Pumpkinhead Horror Head II, wear Pumpkinhead II ____
Trick Staff - wear non halloween weapon or nothing Trick Staff II - non halloween weapon/nothing Pumpkinhead - non Halloween hat/nothing Pumpkinhead II - non Halloween hat/nothing
Of course if you have the hat you want, but are still stuck on staves, you can equip either the Horror Head or Horror Head 2. They should stop giving you hats at that point, and only pass out Lanterns or staves. Same should work the other way, wear a Treat I or II staff and only get hats and lanterns.
It still takes some time to get them items knowing this, but it should work for everyone. I wasted 200k + trying to figure out my mistake on my main, and have gotten the items for at least 5 alts for less than 50k since figuring it out. I hope it's not too late for ppl to get this info and find their Halloween gear. Good luck to all~! ^-^
About 1 hour 40 min after reading this post and 15k in Oranges i got the remaining 4 items i needed. (YAY ME 8/8) If some say that this isn't the only way it is done, then i would say it's still by far the fastest!
Also, i would like to add my findings. The last few items i collected were done by standing at 1 NPC till it paid off, even a "Jack-o-lantern". Soon as i got anything, i would move to another NPC that gave me a different costume. Before i made full circle of all costumes, i would obtain a rare/ex item. Not saying only Yag costume NPCs give "Treat Staff II", but soon as NPC that give you a Yag costume pays off, dont do Yag costume again till you get one of your rare/ex items.
Anyways, helps pass time trading all those oranges if you have a plan. About 3 hours and 30k investment isn't to bad for 8 rare/ex's. Thank you FrostAdora for you post, till i read it i thought i would have to wait till next year to get the rest of my items.
I say keep this as a THF. Just switch it on for SAnTA at the right time, but not if you're gonna use Viper Bite, in my opinion. I don't know which will give more hate...
As long as you don't forget to take it off the moment you're not able to handle the hate anymore.
Would be really nice if you're the backup tank: Main tank can't hack it anymore, slam on the Horror Head II. When the main tank is OK again, take it off. Might save on how much abilities you have to use to get hate, and make it easier for the main to grab the attention of the mob back when he's ready.
Of course, you can only use it for about 25 minutes every 4 days. (rough guesstimate off the top of my head)