@Jeremy908
As @Helen3 mentions, there are 2 different categories for cancellation policies (standard and long term). One policy is for short term (less than 28 days) and the other is for long term stays (28days or more). You choose your policies in the Listing Editor/Cancellation Policy:
Special Offer
Yes, you can send a special offer. Be sure to include the total price for all nights, plus any fees like cleaning fee, addl guest fees, pet fees. Airbnb will apply the taxes and Guest Service Fee.