Hello Ashley,
On behalf of the Disney Parks Moms Panel, I would like to congratulate you and your fiance on your upcoming nuptials. A "Disneymoon" sounds like an amazing way to celebrate. My husband and I honeymooned at Walt Disney World and had the time of our lives. It is fun to go with children, but it is also a blast to travel as just adults.
Your surprise is sure to please your fiance if he is a big Star Wars fan.
The Galactic Spectacular Dessert Party has unforgettable views of the fireworks along with some delectable treats. What more could you ask for?! To answer your question, though, it would definitely be ambitious to do all of that in one evening. The two shows,
Fantasmic! and
Star Wars: A Galactic Spectacular, are often scheduled about 30 minutes apart, so I would hate for you to be rushed getting from one to the other. However, if your tickets are park hoppers, you could try to do one on one evening and the other another evening. Even if you do not plan to go to Disney's Hollywood Studios on two different days, the park hopper would allow you to go just for the evening festivities. Lastly, at this time, the October dates for the dessert party are yet to be posted, so you will need to keep checking as it gets closer. Special events like the dessert parties can change without notice, so just keep that in mind.
I hope you have a wonderful trip. It will be here before you can say "supercalifragilisticexpialidocious!"
~Allison L