Many of the French in our area married into the Cayuse and Nez Perce tribes. The Confederated Tribes of the Umatilla is a consolidation of the Cayuse, Umatilla and Walla Walla nations. I live 30 miles from the reservation which is at Pendleton, Oregon. I imagine the "Kaiouss" is a variation in spelling of Cayuse.
So far, I've been unable to find anything further on Joseph and Susan, so your information on the marriage is welcomed. I'm almost certain this is the same couple. I found them in an old 1850's census of Marion County. It was still Oregon Territory then. It listed Joseph's birthpace as Quebec and I forgot to add that to my original posting.
Thank you for the reply and hope you have success in finding your family.