This post has some photos trying to compare some of the American Girl blue eye options, as well as some of the blond wigs. This is in an effort to help someone who is working on a custom doll, but I thought it would be a good post that might help others doing similar projects.
Kit's hair is definitely a more golden/yellow blond. The CYO wig is a two-tone blond sort of light and dark blond hairs, sort of on the cold side. Mckenna's hair is in the same general shade as the CYO wig, but it has a redder tone in it.
Mckenna - Light Blue
Marie Grace - Aquamarine
Kit - Dark Blue
Saige - Turquoise
It's hard to get the colours to show true to life, so there are photos of each picture with and without a flash.
Marie Grace's eyes are definitely a light blue on the green/grey side. They don't give you a really "blue" feeling, but they're definitely not grey.
Saige's eyes are slightly lighter than Kit's with a definite turquoise feel. They look quite water coloured.