re: Filing a credit card dispute - what's the likelihood of full approval?

I run a team that handles these disputes (called Chargebacks) from a merchant standpoint, and it really boils down to the issuing bank.

AirBNB's terms of service likely spell out cancellations due to weather (I think it specifically references refunds due to mandatory evacuations only), so based on that you're technically screwed. However, quite often issuing banks will side with the card holder anyway (because that's their customer).

I'd say you have about a 50/50 chance. Your chances would be closer to 80% if you had used an AMEX (they are notorious for siding with the cardholder).