Hi Alexander! That is a great planning question! You came to the right place! Making sure that you can make it from one event, attraction, or reservation to another is a great way to think about planning your vacation itinerary!
I’ve got good news for you! Walt Disney World Resort theme park shows are usually right on schedule as posted! You should be able to enjoy Mickey’s “dream” in
Fantasmic! with plenty of time to get to your out-of-this-world dining reservation at
Oga’s Cantina over at Star Wars: Galaxy’s Edge! You won’t even need to “make the jump” to lightspeed.
The one thing to keep in mind is that it can take quite a while to empty the amphitheater after the performance of Fantasmic! It might be helpful to sit toward the rear of the amphitheater so that you can make a slightly faster exit. You’ll still have a good view of the show!
By the way, great job "smuggling" a reservation at Oga's Cantina! It's quite popular! And, as long as you're not a youngling, I recommend the Jedi Mind Trick!
Happy planning!
Jonathan