I think blue and yellow go great together. That yellow really pops against that dress! Also that dresss is really flattering on a lot of body types; my BMs are wearing it in pistachio. Are you doing any other colors with the blue and yellow?
Our colors are navy and yellow and so far everything is looking awesome together. We went with white daisies and yellow roses in our bouquets with some small navy blue accent flowers. The flower girl's dress is navy with white daisies all over it. Very cute!