Re CGM:
I saw a family with two kids under twelve appear for the interview. At times, the consular officers have used their discretion to let the kids stay in the waiting area. The kids do need to come to the consulate when they are included as dependents. (Don’t know about kids who were born in the US and are US citizens by birth.)
As an aside, food is permitted in the consulate, especially for kids. Although the security officer didn’t let us in with our drinks, they allowed packaged items – cookies, doughnuts, chips, pretzels, etc.