There's 5 composers according to the latest Iwata Asks. Kondo only composed the opening theme. Groose's theme sounds so much like the Pirates theme from WW, so maybe Nagata is involved?
I think I hear elements of Minegishi in Faron Woods. So Wakai, Kondo, Yokota, Minegishi & Nagata is my guess. Credits will probably leak within the next few days anyways.