Mine is 12 and not a pup 😂 but when we got him we made as much noise as possible, tv, washing machine, vacuum, door bell, I played sounds on my phone, babies crying, played music, clanged pots, then played the noise of fireworks, right up to letting them off in his presence.
We have done this with all 3 pups. None have been afraid of fireworks. I can walk my Lab on 5th Nov at night time, he’s not phased. He’s had fire crackers thrown at him by some little darlings, again not bothered.
Obviously you don’t have much time, but I would make more noise than usual. Walk them well in the day, or go to the beach, get some chew toys, kongs, lick mats, make a den- just chairs and blankets will do. Do not overly fuss them, but be accessible. Act as if everything is fine, it’s normal. Turn the tv up.
If they’re petrified I’ve heard vets will prescribe Xanax. There’s CBD oil, calm diffusers, vests, ear defenders.
Good luck. Despite col I think it’ll be bad this year.