Yes Yorkies and children mix quite well. You have to make sure that they learn to respect each other. Give them both bounderies. I have three children and a boxer and a 10 month yorkie. My children are not allowed to run in the house and are not allowed to carry Snickers around. My dogs are not allowed in the play room or in the childrens bed rooms. Also, if you get your yorkie first I would try to get him around as many "gentle" children and babies as possible. Make sure that none of the children are rough yorkies don't forget anything. You want to make every experience a good one.
Have a great day!!