I am in a similar situation. I am caucasian - medium tone with dark hair. My oldest son is dark complected due to a suspected Latino heritage. Sons #2 and #4 have my skin tone with light brown and medium brown hair, respectively. I have adopted through foster care and always assumed I would adopt children that were minority or multi-racial. Little did I know Son #3 was going to arrive. He is the half-sibling of one of my sons and is a pasty white boy
I have gone through more sunscreen this summer than I have in the past three years! Anyway, even though his skin color is much lighter than anyone else in the family, he fits right in because he has facial similarities with his biological brother.
I think you have to make choices that are the best fit for your family. When I was "looking" for waiting children to adopt, I stayed away from the fair-complected children for the same reasons you are conveying.
Good luck!
Sam