Executive Meddling: The darker tone during the last season is said to have been in response to the network not liking that the show's primary demographics had fallen out of the coveted 18-40 range.
Fake American: Jane Seymour is British. In fact, she used to be a Bond Girl. It's not exactly clear whether Quinn's accent is supposed to be some version of upper-class Bostonian; her family talks roughly the same way.
Cloud Dancing, a Cheyenne shaman, is played by Osage/Cherokee and Lakota actor Larry Sellers.