What breeds work as 'hypoallergenic' is highly variable from person to person. There's no true hypoallergenic dog breed, but dogs with hair - curly or wiry - don't shed as much and therefore often keep dander and other allergens they might collect on their coat (dust, pollen) more contained rather than floating around the house or sticking to furniture. Probably helps that curly breeds are bathed more often on average, too, since they need regular grooming.
What I'm saying is that, if you want to be very sure the dog works for your household's allergy concerns, go with a breed that you absolutely know the allergic person/people respond well to (like another Wheaton), or go meet adults of the breeds you're considering and spend time with them to better judge how they work for you. I've known people who could live fine with wire-haired dogs but had trouble with poodles, who are the quintessential 'hypoallergenic' breed you hear recommended.
Be very, very careful with crossbreeds like Cavachons. Because they haven't been carefully bred for a consistent coat type over many generations, they can often vary quite a bit when it comes to how much they shed and how easy it is to manage their coat - and, of course - how an allergic person may respond to any given individual, even within the same litter. By this same token, the unfortunate truth is that it's much harder to find someone breeding mixed breed dogs responsibly - that is, doing thorough health testing and temperament evaluations to produce puppies that are as healthy and stable as possible - than a responsible purebred breeder.
Health testing is especially important in this case because Cavalier King Charles Spaniels - the 'Cava' part of a Cavachon - are lovely, lovely dogs but have devastating health problems. It's no joke. Over half of the entire population of the breed has the terminal heart condition called Mitral Valve Disease by only five years old. Almost all of them have it by ten. And that's not the only serious health condition in the breed by a long shot. This is not something that vanishes just by breeding a Cavalier to a different breed, and I would personally be extremely picky about how a breeder was managing health issues in their lines if I was getting a dog with any Cavalier in it. Breaks my heart, because they're such delightful dogs.
