Well, then lets have a look at it ...
Pair 1: Kim Raffo & Amber Lynn Costello
different apparent age (and in appearance, Raffo looks even older than she was), different face shapes, different eye shape and color. The only thing a little similar is the hair color, except that ALC has those blond lines (what are they called in English?) colored in.
Pair 2: Barbara Breidor & Maureen Brainard-Barnes
That's an entirely different face shape. Maureen's cheekbones are low, Barbara's high, hair color different, eyes different in shape and color. Hair color different, age group entirely different also in appearance.
Pair 3: Molly Jean Dilts & Megan Waterman
Well, the hair color is as different as it can be, but at least those two have about the same face shape up till the cheek bones. Except that the upper part, forehead and therefore the eye brow line is entirely different.
Pair 4: Tracy Roberts & Melissa Barthelmy
Different hair color, but at least both in the blond range. Entirely different face shapes, caused by entirely different width and position of the cheek bones, Melissa has a much higher eye brow line also.
So, honestly, four pairs and in eahc and everyone different face shapes, different eye colors and shapes, in at least two of the pairs visible big age differences ... where are the striking similarities? Maybe you should have added that those similarities only exist in your opinion? Because I can't see them. But you are presenting your opinion as fact here? Even against measurable differences. Because the face symmetry is on those pairs also different.