From watching the behinds the scenes featurettes and trailers, I think I see there is going to be a change to the ending in the movie. In the end of the book,(spoiler) the big showdown with Lena and Sarafine happens during Link's concert. Though I think in the movie, the big showdown happens during a Civil War reenactment, which would explain why all the main actors are wearing those types of clothes shown in the trailer/featurettes.
I might be wrong though, it's just a theory, but I might be right too. I won't know until I see the movie, and I can't wait! :D