Congratulations to your granddaughter, Ben! #1 sure is a sign of the times. She looks the most natural/relaxed in #4. The few times I tried to shoot portraits of my husband, I found it super difficult. I had a patient who was a portrait photographer (studio work). She said she just had a gift for making people feel comfortable. I'm sure your granddaughter is comfortable with you, but maybe not so comfortable with posing. Figuring out what to do with their hands is a big one. #2 almost works that way, but it also sorta looks like she has to pee......

I think they would all make for good head shots.