ok, i have a few questions about hallows end and some raiding stuff as well. First of all, is it possible to just walk into the scarlet monestary(as a lvl 85 undead hunter) and defeat the headless horseman multiple times, or can that only be done once a day, and if you can, would it be possible as a lvl 85 undead hunter? second, for the trick or treat thing, what is the total % to get the hallowed helm(I figured that a 50% chance to get the treat bag, then, %5 to get the hallowed helm so, %45?) 3rd, can you manually reset a raid(if you enter a raid, then the boss dissappears in the middle of a fight for some reason, and then u want to reset the raid and try again)? 4th, where is there a list for enchantments you can put on your helmet item? please respond asap. thank you!

The Headless Horseman will be level 85 this year, you will not be able to solo him and the adds. You can press "I" and choose to queue for this dungeon. Queues go pretty fast for special events. You can run as many times as you want BUT you will only get a loot bag once a day. The loot bag is what will contain the horseman's mount. If the drop rate is anything like the Kodos your chances should be pretty decent.

The Hallowed Helm also drops from the treat bags you get from the inn keeper every hour. I have several on my low level banker toons. Percentages are low. Much less than what you have quoted.

If your raid bugs you can try a soft reset by EVERYONE exiting the instance and waiting for about 15 mins. If this does not fix the issue you need to open a GM ticket. (that's the red "?" on your bottom action bar)

Enchants are here:
http://www.wowwiki.com/Enchantments_by_slot

More info on the Hallowed Helm:
http://www.wowhead.com/item=33292/hallowed-helm