My preference would be for the highest level the DM is comfortable with so as to play with as much of the ToB's unique material as possible. As for books, perhaps automatically include SRD and ToB stuff, and leave all sources beyond that as possibilities requiring DM approval. The world should probably capture that anime-infused fantasy feel. Maybe a blend of Oriental Adventures and Eberron? Or, even better, a homebrew that steals shamelessly from Princess Mononoke, Ninja Scrolls, or works of a similar vein.