@Robert219 to answer your first question, if you received a Reservation Request, yes, since you have to Accept or Decline. If it was an Inquiry, then no, just responding within 24 hours suffices to preserve your response rating. In the case you mentioned, I presume it was an Inquiry asking for a one night stay, correct? If so, then you could just respond and decline since they were asking for a 1 night stay where you have a 2 night minimum.
As to your second question, who cancelled? You or the guest? Either way, if the reservation was affected by the hurricane, both you and the guest would be covered by Extenuating Circumstances, but the party who cancelled should contact Airbnb before cancelling to avoid penalties (host) or to receive a full refund (guest).
Search Airbnb's help files for Extenuating Circumstances to see what they are.
Hope this helps, Clare