Here's a question: have you actually crate *trained* the dogs (as opposed to simply putting them inside crates?). It is very important, as there's a huge difference between the two approaches and crates should never be used as tiny pens for dogs that have not actually been specifically trained to use them.
An owner can seriously stress them (and create additional, long term anxiety problems) by sticking them in crates if they are not trained to accept them and it sounds like they were not crate trained before you got them, going on your description? If you were told they were, I think they definitely are not, as crate trained dogs are relaxed and happy in their crates. Do you have something like stuffed kongs to give them when they go in their crates so they have something to keep them busy, too?
There is a lot of information on crate training and separation anxiety in the Library section in Caring for your Cavalier. There's also lots of information on these topics from trainers in the training links pinned to the top of the diet and training section.
I cannot stress enough though that you absolutely MUST work on training them first before crating them. I'd suggest in the interim, getting an exercise pen (xpen) and penning them which most dogs are far happier with anyway, especially initially, and then work to crate train.
I find my xpen one of the most useful and versatile things I own!
I'd also strongly recommend getting one of Dr Ian Dunbar's excellent manuals on raising and training a dog as it will be an invaluable resource in answering all sorts of questions while also giving you a framework for managing dogs -- especially two, which is considerably more difficult than one. Ian Dunbar's books are widely available from Amazon and other online sites.
You never want to put your dogs, especially young dogs, into stressful situations that can cause lifetime fears (an already relaxed, well trained, confident dog is a different matter). My dogs are
mostly indifferent to fireworks but that is for fireworks going off on Halloween and I worked to train them to be fairly relaxed around such noise, though they still make Lily bark like mad
-- but I'd never actually deliberately take them to where they were going off nearby. Most dogs find them terrifying (it is a major owner issue for most people at certain times of the year) and mine can get scared if lots are going off near to the house at one time. Every Halloween over here, a huge number of dogs end up in the pounds and go permanently missing after they bolt from their homes when fireworks go off. It is the single worst time of the year for rescue and pounds as so many are suddenly homeless.
