The characters like Mickey and Minnie have rather clumsy hands and limited vision, so they would not be able to hold a child. The ones like Belle and Cinderella would be able physically to hold a baby, but I don't know if they are allowed to (you never know when a baby will spit up or leave a damp spot on the lap). If that happens, it would mean a quick exit for the character and a change of clothes. Besides that, many babies cry when handed to someone they don't know, so they may not want to pick up babies for that reason. I have seen lots of times where the characters will bend down (or for the more mobile ones, even kneel down) to get close to a baby in a stroller. How about doing that or getting mom or dad in the picture with baby?