Overdressed? Undressed?
They are both basically in mini-dress.
I'll shamelessly rephrase something I read under the twitter source here:
Basically, Aubrey's dress is designed to be worn to a more upscale (albeit not-too-formal) occasion due to its more form-fitting cut and its black color (= more subdued and "classy", pretty close to an evening/cocktail dress). Evan, on the other hand, is wearing a pink, polka-dotted sundress, which is worn in more casual settings. So even though they're kinda similar, fit and color make each other think they've gone too far in either direction.