There are anime shows/manga series that you can adapt and cast with white people. For instance: Full Metal Alchemist, Attack on Titan, Black Butler, Baccano, Cowboy Bebop, Helsing, Rose of Versailles, Princess Tutu and an anime that’s airing right now (and I love it!) called ACCA 13. All of these take place outside of Japan and have predominatly white characters. Adapt them.
Anime/manga like Death Note and Ghost in the Shell are deeply ingrained in Japanese culture. You can’t adapt them with a white cast and expect them to still have the same meaning. Do better.