Now that I can Wild Shape into Large animals, I think it's time I started making use of my Natural Spell feat. Standard preparation for a fight will now include wild-shaping into a brown bear, then buffing myself and Neshi with Barkskin.
Belaver tries to heal his companions faster than they can kill each other, recognizing that he can neither kill the cultist nor restrain the larger, more martially inclined among the party.
Waiting for the cultist to start casting another spell, then trying to peg him with a sling; also, commanding the elemental to resume non-whirlwind form and attack the spellcasting cultist.
"We are running very low on wands of healing, and I have a feeling that our need for them will only increase as we continue. If the writer of this letter can be trusted, we should not be overhasty. I would advise a trip back to town, to resupply."
I would suggest southeast, as it is not alerted to our presence (well, to our presence in specific; they're probably aware that something is decidedly amiss).