Actually, they are a perfect example of genetic diversity within familial relatedness.
If you take the blondest one and the darkest one, lined up, they would not look at all related. But if you throw in the other sisters with the in-between colourations, you can see how blending of characteristics works. So from Africans to Swedes, our two extremes, we have all the colours of the world.
Am I right in thinking the theme of this is principally Crete? I identified the Phaistos disc and a Minoan Snake goddess but was not sure about a second disc with two winged men and a third non winged man killing a bull like creature: if I am correct that would be Theseus, the Minotaur, Daedalus and Icarus,