Hum... I'd go for the earth tones. She obviously loves them, blankets are used most often in winter and she'll be wearing those colors. Course knowing me I'd do something like put brown (tan and all shades in between) and turquoise (or pink or yellow) together, then you'll have a happy marriage of both.
Good luck, can't wait to see it!
By the way, I have recently had a few Mom's request light summer blankets. We've made them out of one layer of flannel and hemmed the edges. Maybe you could do a pretty quilt for winter and a few simple wrap blankets for summer. All the gals I made them for seemed to want them to be smaller for while the baby was small, 30x30 (finished size). Also to make the hemming super easy you could use bias tape.
Ohhh I love baby gifts! Just not soo sure about crying babies.