3. CANCELLATIONS/REFUNDS: Cancellations may be made by telephone or in writing. Changes to the vacation commencement date or changes of Guest names are subject to cancellation fees, stateroom and occupancy availability and prevailing rates at the time of the change. For cancellations, amounts paid, minus cancellation fees and other amounts owed, will be promptly refunded. The cancellation fees will be assessed regardless of resale of stateroom or hotel room. No refunds will be made in the event of interruption or cancellation by the Guest after vacation commencement date or for any purchase of a Category with Restrictions (Inside, Outside or Verandah). All appropriate refunds will be made directly to the Guest’s credit card account or through the Guest’s travel agent if the reservation is made through a travel agent.
Disney Cruise Line will not be responsible for the receipt of refund monies by the Guest from the travel agent. All travel documents including airline tickets issued by Disney Cruise Line must be returned before refund processing can begin. Please note that certain travel agents may withhold an agency cancellation fee. For your peace of mind, we recommend the purchase of the Vacation Protection Plan.
CRUISE CANCELLATION FEES:
CATEGORIES WITH RESTRICTIONS: Reservations for Inside, Outside or Verandah Categories with Restrictions are NON-REFUNDABLE and NON-TRANSFERABLE. A 100% cruise cancellation fee applies from time of payment.
Cruises 1 to 5 Nights where Embark or Debark is U.S. Port
Days Prior to Vacation Commencement Date Fee Amount
74 to 45 days Deposit per Guest for Non-Suites/Concierge Staterooms
44 to 30 days 50% of vacation price per Guest
29 to 15 days 75% of vacation price per Guest
14 days or less No refund
Cruises 6 to 9 Nights where Embark or Debark is U.S. Port
Days Prior to Vacation Commencement Date Fee Amount
89 to 56 days Deposit per Guest for Non-Suites/Concierge Staterooms
55 to 30 days 50% of vacation price per Guest
29 to 15 days 75% of vacation price per Guest
14 days or less No refund
Holiday Sailings*: Cruises 1 to 5 Nights where Embark or Debark is U.S. Port
Days Prior to Vacation Commencement Date Fee Amount
89 to 65 days Deposit per Guest for Non-Suites/Concierge Staterooms
64 to 43 days 50% of vacation price per Guest
42 to 15 days 75% of vacation price per Guest
14 days or less No refund
Holiday Sailings*: Cruises 6 to 9 Nights where Embark or Debark is U.S. Port
Days Prior to Vacation Commencement Date Fee Amount
104 to 75 days Deposit per Guest for Non-Suites/Concierge Staterooms
74 to 43 days 50% of vacation price per Guest
42 to 15 days 75% of vacation price per Guest
14 days or less No refund
*Holiday Sailings are sailings that include Christmas Day, New Year's Day, Thanksgiving Day (US) or July 4th.
Cruises of 10 days or More and Cruises Less than 10 days where Embark and Debark is non-U.S. Port
Days Prior to Vacation Commencement Date Fee Amount
119 to 56 days Deposit per Guest for Non-Suites/Concierge Staterooms
55 to 30 days 50% of vacation price per Guest
29 to 15 days 75% of vacation price per Guest
14 days or less No refund
Suites and Concierge Staterooms: All Sailings
Days Prior to Vacation Commencement Date Fee Amount
90 days or more Deposit per Guest
89 to 56 days 50% of vacation price per Guest
55 to 30 days 75% of vacation price per Guest
29 days or less No refund
For reservations made prior to March 3, 2015, the cancellation fees assessed will be based on the cancellation fees listed on the original confirmation unless the sailing date or vacation package is modified.
Is Disney usually pretty flexible on dates that you want to have the wedding ceremony on a 
I did my wedding in the atrium and even got to walk down the stairs so I totally get not wanting to do a Castaway wedding, we also had about 30 people. I would really talk to your coordinator about an indoor wedding and they work better on port days, because more people are off the boat, my wedding time was 1:00pm that was as late as they could do it and we had the cake ceremony around 2:00pm, you should check out my PJ its in my link it has all the information on doing a wedding onboard! Good Luck 
Hope I don't get in trouble, but you can find the info on the website as well.
.... Does your 3 night cruise itinerary have an at sea day that your hoping to have your ceremony day be on? I haven't seen many 3 nights with a sea day!
