In the first picture: The blonde. The brunette looks sort of ratty.
In the second set: Circa the times the photos were taken? Britney. At the least, doing horrible things to her for making pop even worse would be poetic justice

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Third: Hermione. She looks so intelligent.
Fourth: The one in the blue dress. As much as I love red, it looks just slightly better on her, and her face is more flatteringly taken in this shot.
Fifth: Scarlett Johannson, though it is so hard to choose given the nice red heels Nat's got