This is pretty common. I would delay submitting documents until both cases are at NVC. I would immediately contact USCIS and request an expedite for the child's case based on the fact that the petitioner naturalized.
That just isn't realistic. Everyone thinks THEIR case will proceed faster. At some point, reality strikes. As my High School history teacher always said (paraphrased):
"To the wise, a word is sufficient"
I wish you well in your journey.