K-4's are a derivative of the K-3 and only need to be listed on the I-129F. There is no G-325A's needed for the child/children until they adjust status in the US.
Once at the consulate they will apply for a visa just as the parent does for the K-3. Someone will be able to give you a list of all that is required and what is not applicable to the child/children.
They will need an I-130 filed on their behalf once in the US in order to adjust status.
How does a K-4 child adjust status in the United States?
The K-4 child will not be able to file for adjustment of status in the United States until the U.S. citizen parent/step-parent files a I-130 on behalf of the child. If the U.S. citizen parent/step-parent never files the I-130 petition, the immigrating parent may do so once he/she has obtained legal permanent resident (LPR) status, but the child would have to wait for an available visa number. Finally, the immigrant parent, upon adjusting status will no longer be in K-3 status, therefore, the child will no longer be in lawful K-4 status, since this is merely a derivative classification, and that child would begin to accrue unlawful presence. http://travel.state.gov/visa/immigrants/types/types_2993.html#Children