I hope I am not being tiresome, but in the last picture you posted, alicia, Margaux now reminds me of Charlotte, especially with your avatar next to it. You are right, Margaux has the tragic etched into her face. Not hysterics, not melodrama, something very real and intense. It almost makes you believe in a sense of destiny, as if she were marked from birth with the knowledge she would follow in her grand-father's footsteps.
I try to see similarities and differences in powerful actresses and think of the roles they could have played. Even though Margaux also reminds me of Monica Vitti, who also has a tragic face, (or Liv Ullman, for that matter), hers is very different. Not lean and aristocratic like Monica in La Notte or L'Aventura, not wholesome yet tortured like Liv according to Bergman, no, Margaux' face is quintessentially American and the epitome of the eighties, the decade of living dangerously. As beautiful as Emmanuelle Beart in Chabrol's "L'Enfer", ("Hell"), but doomed, doomed, doomed. In "L'Enfer", Beart's face remains whole, as it is her husband who projects his own hell onto her, but Margaux's hell is her own creation and her face is, as you say, Boomer, "one minute away from breaking in tears", one minute away from betraying her dark side. She wears her secrets not on her sleeve but on her face, and looking at her is almost painful. Looking at Michelle, by contrast, is always soothing, always a pleasure, she really looks like an angel at times, although according to you, Boomer, it might be more of an angel of temptation.