Can you tell me about these dog breeds?

The Papillon is a very high energy dog- think miniature Border Collie. Of the 3 toy breeds you mentioned, they are the brightest & most active. They will need to be brushed every day or two, but they do not need to go to a groomer. Paps are highly intelligent & need to be kept busy or they will make their own fun, which may not be good. Paps are not yappy as long as they are trained to be quiet. They are clean & do shed, but not a lot. House training a toy dog can be challenging. They will need daily exercise, but a walk or play in a small yard will do it & Paps do love to play! They are not good w/ young children as little kids can easily hurt them. They generally live into their mid teens & are usually quite healthy when from reputable breeders. If you are looking for a more sedate lap dog, only an older Pap (10+) will most likely be that way. The Cav & Pom would be lower energy dogs. I like those breeds too.