I have no information regarding the identity of Jean and John, but I would bet they are the same person (John being English for the French Jean).
There is an article you should read in regard to this family. Go to www.Idahostatesman.com and click on Idaho History. The name of this article is "In Sacajawea's shadow" and is dated 5/20/2003. At the end of the article, are sources for the information given that may also interest you.