I'm not sure that the pictures from Alaska Dispatch showing scenes from a taping done at Sarah Palin's "Superbowl Commercial" show us much more than the Guv's love of cameras.
It is pretty clear that Trig is in the crowd, along with Chuck Heath, Sarah's father. Then there are two girls who trade off holding Trig. One wears a reddish top and the other, a white sweatshirt. Neither of those girls looks pregnant or post-partum.
The images below show the best shot I can get of the girl in red (reportedly taken in late January 2009), and then press photos of Bristol and Willow Palin around September - October 2008. The second image of the girl in red has been de-speckled and sharpened somewhat.
The girl in red's nose/mouth/chin looks wrong, that is, if we suppose it might be Bristol. Bottom line, the images from the Alaska Dispatch are too poor quality-wise to tell very much.