When John Boy and Erin are speaking outside the house, the shadow on Erin's face changes. In the full shot, the right side of her face is mostly sunlit. In the medium shot, her face is in full shadow.
Corabeth and John-Boy have a discussion about her father, and Corabeth says that the other children weren't even thought of yet. If John-Boy was old enough to remember her and her father, Jason and possibly Mary Ellen or even Ben would have been born (or on the way) by then.