Hi,
First, welcome to Pathfinder!
There was some discussion on this topic this thread.
There are some additional rules for haunts in the Pathfinder Reference Document: http://www.d20pfsrd.com/gamemastering/haunts
I think this was the main post that would answer your questions (mainly the second point on destroying haunts):
Brandon Hodge wrote:
Stonesnake wrote:
I find the Haunts quite interesting and I can't wait to run them, however I have several questions about their mechanics as my players are very much rules-lawyers and will want to know EXACTLY how they work.
I should say up front that I have a KQ article addressing some of these very same questions in the works -the same sorts of questions I had as I wrote the haunts for my Haunting of Harrowstone article. So, if you promise not to tell anyone I'll spill:
1. Attacking Haunts
The rules already address your first 3 questions in the 4th section under "Haunt Rules": On the surprise round in which a haunt manifests, positive energy applied to the haunt (via channeled energy, cure spells, and the like) can damage the haunt's hit points (a haunt never gains a Will save to lessen the damage done by such effects, and attacks that require a successful attack roll to work must strike AC 10 in order to affect the haunt and not merely the physical structure it inhabits). Unless the haunt has an unusual weakness, no other form of attack can reduce its hit points.
So, there you go. Hit AC 10. Haunts get no Will save if you're using cure spells. Viola! Personally, I think AC should be 10+haunt CR, and they should have the incorporeal miss chance, but I'm a mean bastard. The holy weapon quality technically doesn't count as positive energy, but as a GM I'd probably let it fly, but only let the weapon deal the +2d6 holy damage, and nothing else.
2. Destroying Haunts
I pretty much covered this in my post above, but here it is again. Most certainly characters are aware of local legends, superstitions, and folklore for dealing with haunts that their players will not be aware of. My suggestion is to handle it the same way you'd handle PCs trying to find other info: with Knowledge checks. Say they face the rolling fire haunt from the March 9th Paizo Blog After they've run into it once, they return to the dungeon a few days later and *poof* it sets alight and starts rolling after them. Again. "Wait a sec!" says the cleric. "I have heard of these things! Everyone turn your cloaks inside out! Merisiel, hand me a knife!"
My rule is to use Knowledge (religion) or (local), with a DC equal to 15+ the haunt's CR. Alternatively, after you've dismissed the haunt once, but before you've figured out how to destroy it, you could try communicating with the haunt itself, with the new rules for rapping haunts in the article's sidebar. It worked for the Fox Sisters...should work for PCs! Pull out the ouija board and have some fun! =-)
