me swap heads on a couple of family photos?

Between my kids and my sisters kids, 7 in all, we never got all 7 of them looking good

.
Unfortunately I didn't take many of them so I didn't see the expressions in camera until after the fact lol. But one of mine and one of my sisters were horrible, I swear it was a conspiracy

Any way when my grandmother finally decides which ones she wants would anyone be willing to help me swap a couple of heads out or atleast give me dumbie steps on how to do it?
And if you do volunteer please don't laugh we are a crazy bunch and it shows lol.
TIA
Breezy