(1) and (2), It is easier, and not to mention a lot less expensive if she could just apply for a reentry permit, which is good for two years.
(3), Are you talking about a baby yet to be born or your child currently liveing in China? A child to your LPR wife also? Each senario leads to a different answer. If your LPR wife is pregnant and will give birth in China, she should get that reentry permit and return with the baby with all documents before the reentry permit expires. They both get to keep LPR. If it is a child born to another woman who was not a US citizen or LPR, you will need to petition for the child in F2A category.
