I can immigrate to the United States at the end of the year or early next year, and I want to apply for my son (1 above). At present, he has not left any information for the US Immigration Service.

According to you, is the schedule up or the visa expired?

As long as it is reserved, all the application materials will be transferred from the Immigration Bureau to the American Consulate in Guangzhou, and any questions after that will only be contacted with the Consulate.

Your son is so young, you can immigrate directly with his mother, and the procedure will not be too complicated. It is correct to send your and your son's materials to Guangzhou Consulate, but you should keep in touch, make sure they have accepted it, and adjust your information.