I think we're agreed on Marie changing little as she aged. Always her inner beauty permeating her outer beautiful face. Probably becoming heavier,but still the merry, fun aunt in middle age.
Age doesn't favor the more sober and melancholic and introspective, and unfortunately that was what Olga was becoming. I think facially, she would have aged quickly, though not necessarily poorly. In figure, I doubt she would remain the sturdy girl she was as a teen and young woman.
I think Tatiana would retain her exotic face , and remain appealing. I agree with edubs though that her leanness and fineness of features is subject to a certain premature aging. I can see her still retaining her characteristic look for a long time.
Who knows about Anastasia? Or which Anastasia? She metamorphed so much and so drastically. I think facially she may have steadily gained in character as she passed her twenties and thirties. Of the four girls, Anastasia strikes me as usually looking slightly older than her chronological age. It's so difficult to judge a girl who never made it to adulthood. In my sixties,I'm still recognizable to family and friends as I was as a twenty-year old, though obviously having passed through several stages of appearance, most for the better.
I think the same can be said for Anastasia.