Ahoy there Joy! (Well, isn't that rhyme just delightful?) Welcome aboard planDisney!
When it comes to using your Future Cruise Credit, you most definitely can be used in collaboration with other offers, at least according to my latest communications with the fantastic Disney Cruise Line crew members!
Now, since the phone lines have been quite busy following the announcement for the
Disney+ Subscriber Special Offer, I'd definitely suggest you find the cruise you and your crew would like to sail on, and then at the payment screen, you should see your Future Cruise Credit balance as an available method of payment! That'll be the smoothest sailing way to check your balance, but if you don't see that option, my next suggestion would be to call a crew member right as the phone lines open at 8 a.m. Eastern time!
It's important to remember that time is running short to use your Future Cruise Credit: All Future Cruise Credits offered due to the COVID-19 operations suspension can be used on or before September 30, 2022. If you are not able to use your Future Cruise Credit, you will be eligible for a refund up to the amount of your original voyage fare.
Thank you so much for your question, Joy. I hope that helps you get ready to set sail and that you have the time of your lives!
SEA ya real soon!
Andrew