It is a very bad idea. The portions at 50's are enormous and you will be stuffed.
I have been to the Star Wars dessert party twice and eat just eat an afternoon snack, but I am not a huge eater. The savory options they have are a flatbread -think, naan, with roasted red pepper hummus and a black bean dip, cheddar cheese, olives, mozzarella cheese, cherry tomatoes, and watermelon. I think that's everything. That plus the desserts is more than enough for me.
Truthfully, I don't like to be too full because I'm there to get my money's worth on booze. Don't judge. And don't forget to take a to go cup.
And PS they will also just give you liquor if you don't want the frou frou drinks and if something like a rum and coke is more the speed of someone in your party. Just tip the bartender.