My ducks sleep through every party. We give. We are the loud party givers here into the middle of the night. When it is around the campfire and we sorta sitting, they come sleep next to the party people. When people are getting a bit loud and drunk they find somewhere else to sleep. But often still nearby. They were not really scared bu the noise of fireworks. But where on look-out mode for the colours in the sky, that they do with everything from the skye.
I think they will be fine.
I wouldn't lock them up if you normally would, or do so at the same time. I noticed that my Indian runner ducks tend to really watch how WE react when it comes to new things, and then decide to be or not be scared.
Good luck!