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
Now if I was to guess to get the Pitchfork you'd need the:
Horror Head II
+
Treat Staff II
Now this is just a guess. Good luck.