I am totally against the deliberate breeding of cross-breed dogs, so afraid I can't comment there.
regarding a Labrador, IMO one must be very prepared for what they are taking on.
Sure, I'd prefer to see a breed of that size with a good large yard to run around in, but you have to take into consideration what you are going to experience with a Labrador for the first couple of years - at least!
A Cavalier is a lovely breed that I personally think would suit a new dog owner perfectly.
As MAC has stated, all dogs have certain tings one needs to look out for when purchasing a puppy, and the Cav is no different. Research as much as you can, meet the dogs if you can to ascertain which breed is right for you, and make sure the breeder you choose to purchase from has done all tests required to try and minimise health issues.
All the best.