What was the reason Tilda Swinton gave for having the blond hair she sported in the movie as opposed to dark hair, which is how the White Witch is usually depicted?
In one of the cast interview segments that I watched today, I believe it was partly to make the White Witch more modern, and to give her an Aryan look about her.
Correct. They also had microcircuits in the minotaur's heads to create head movement and facial expressions and it made the wearer hard of hearing as well.