That sounds like a hard one
The first thing to think about is you've already got cats. Dogs and cats CAN get along, but a lot of the time they don't. Have you ever seem their reaction to a dog? Especially a dog in your house?
Because the cats may well be fine with a dog, and if you get a puppy it will grow up with the cats so it will be fine with cats.
Cavapoos are adorable. But like you said they are prone to separation anxiety. That takes a lot of work to prevent it. But if you always have someone in the house that's probably not going to work. Which means going on holidays would be a lot harder. Because you would need to find someone who is always at home.
You also now have to go and spend a whole lot more money on all the stuff for a dog - when you already have majority of the stuff for the hedgehog.
Hedgehogs are not really family pets. They tend to bond to only one person, sometimes two, but not a whole family.
But they make amazing pets.
And they are funny to just watch. And their cuddles if you get a cuddly hog are honestly amazing.
Thats not to say you can't make it so that everyone gets a bit of enjoyment out of the hog. Its harder though.
But again with a hedgehog you still need find someone who can look after them when you go away, and who will keep the schedule and make sure the temp is right when you go away.
They also have handle the hedgehog so you need someone who is willing to do that even if they are spiky and huffy.
Have a look at who can look after the pets when you go away which pet do you trust people looking after more?