I haven't found the direct link to Buatte's in the western US, but I'm sure they're related. Unfortunately for you, though, I don't have any information about them. I do know a good number of people from around St. Louis, including a number of Kaskaskia, IL, and Ste Genevieve, MO, residents ventured out on the Oregon Trail for Catholic missionary work. This is where I presume the Buatte's originally came to Idaho, Utah, Nevada, California, Oregon and Washington.
Sorry I'm not more helpful!