Funny... I've noticed the very same characteristics in MY little crew!
Flower is a pretty classic sable and she is the clever/naughtiest one of
all... followed by Pandora, also a variety of sable (though a lot lighter;
I think she is 'panda' colored, actually).  The dark ones definitely are in
charge over Tank, the silvery-white boy; also, he is dark-eyed and deaf,
and he never dooks, only hisses and pants.  The lightest girl, Pandy, is
the head of the household and is much quieter than the darker sables.  So,
yes, from my personal experience, I see the same color/behavior pattern
emerging that you noticed!
[Posted in FML issue 2498]