New Year's reminder:
If your bunny's neighborhood is firecracker noisy, keep the buns cool and quiet.
Close the windows and doors. Close the blinds to reduce flashes.
If needed to "cover" firecracker noise, play music - peaceful, easy listening (not loud).
Your TV service might even have a suitable channel in its lineup - you just never tune to those channels. We have an air filter that runs all the time and provides a white noise background.
If you do not already have boxes for them to play on and in, get some plain cardboard boxes (not slick or a lot of ink/color; no staples, labels or tape). Cut at least two openings in each box big enough for your bunny to get in and out ... they can hide in them, to further mute the noise and feel a little safer.
Keep them company and reassure them that everything's okay. Pet them if they are the petting kind of bunnies. Have a couple of healthy treats handy.