If you get a puppy then it is entirely the owner's responsibility to try and give the dog proper training and time and socialising that will determine iof it is good with kids, dogs and cats. But as Cathy notes, in addition, all individual dogs vary. I have two dogs that are not very keen on children. They are also very small as puppies and need constant supervision around young children and vice versa. Many do not like cats. A puppy may grow larger than carry on size for a plane. This is a breed that often gets a bit larger than breed standard and thus goes beyond carry-on size.
Cavaliers shed a LOT. They need to be groomed daily ideally, or at minimum many times a week.
You would be very unlikely to be able to acquire a dog of show quality without putting in some time getting involved with your regional cavalier club, finding a professional breeder willing to mentor and work with you for a while, etc. Very few breeders -- and none with healthy, good quality dogs -- would be willing to sell an intact open registration dog (eg show quality) to someone who hasn't proven themselves over time in some context.
I'd suggest two things: first, if you have lots of questions, especially if many of them are very basic, please use the Library section and the search function as probably all will be answered by the very large collection of basic articles I have in the Library on all topics, and also, probably will have been discussed already in the past. People are always happy to help answer questions but it is more thoughtful to not expect or ask people to answer lots of easily researchable questions and instead save queries for issues on which you need opinion rather than fact.
Second: I'd suggest going to some shows and talking to some breeders to get a better idea of whether this is the right breed for you and to get direct advice on how to get involved in showing.
This board has primarily a pet focus though we do have some experienced, reputable breeders here as well who show. But I know they will basically suggest the same -- that you need to get involved with the clubs, get to shows, learn about the breed from people involved in showing the breed, and find a mentor.
Beware of anyone selling supposed show quality dogs over the internet or willing to sell them without expecting you to work closely with them and learn all the ropes. Good breeders just do not sell show prospects in this way but many trash breeders dupe novices into buying their mediocre dogs in this way.
