I believe Liz Cheney has three little girls and her baby boy was a newborn at the time of the election -- I remember her holding him on the stage at the Reagan Building the day after the election -- so I'm thinking this is the youngest granddaughter sitting with the VP?
I think you're right. After I wrote that it occurred to me that the boy could not possibly be as old as that child. It has to be the 4 year old. Adorable face, that's about all you can see. It seems like they'd have some gloves on her, her hands must have been freezing.