Its the bouncy ones that the child should avoid at first as they are so eager for a fuss they jump and it can be daunting.
Have you any friends or neighbours with a calm dog, so you can both watch the dog pootle about, chatting about its tail and hair, ears, wet nose etc. the child will become used to body language of this dog. and slowly and surely will get more confident. Be sure to point out the "friendly" body language, so as the child is learning about this dog, he can see it is not bearing its teeth (which is a sign of anger or attack), and will therefore learn how to spot a friendly dog and spot a not so friendly dog. You could also play the idiot and ask the questions to the owner, so the child can hear the answer, the child wont feel their thoughts are silly if you are the one asking the questions.
As for children and dogs, the right dog is wonderful for a child. I had a border terrier, and she was like a sister to my daughter, they played together, slept together, how many children have played barbies with the dog, mine did, and the poor dog would come downstairs wearing a frilly dress, odd socks (4 odd ones) a hat, and sunglasses on many occasions. She looked better in dungarees though.
The important thing is to teach the child to respect the dogs feelings, and that it is understood the dog feels pain, and the signs when the dog has had enough. (Mine would just get up and walk away, and if followed would keep walking, daughter soon got bored and would let her wander off.) Saying that she never chased her, just tagged behind the dog.
I asked my daughter "How did it feel to grow up with a dog" and she said."There was someone I could get up to mischief with, there was always someone to play with, always someone to cuddle, and be cuddled by"
I grew up with a dog as well, she was quiet, and gentle, but was so sweet she gave me love, and support and never told my secrets or worries to anyone.
just for information, it is important for you to teach this child to be confident around dogs, even if they have no desire to interact with them. If a dog is nervous, and comes accross a nervous person, they both sense each others nerves and will both overreact to each others movements, that same nervous dog with a confident person, wont be worried if they can tell what the person is about to do, say walk past them, not stopping , just going past, the dog will just watch the person, whereas, the nervous person will stop, look at the dog, step forward, stop, look at the dog, and the dog will have no idea what the person will do, and may become defensive- which is where the over reacting to each other kicks in.
(I hope you can understand what I mean)