The Charles St. Andre you mentioned is a son of Joseph Botquin dit St. Andre and the family dropped the Botquin and used the St. Andre as the family name. The first ancestor that I have traced is Pierre Botquin dit St. Andre that came to Canada as a French Marine. He was stationed at Montreal and then he moved to Boucherville, then to Fort Mackinac, back to Boucherville, where he built a new home. Joseph had many children and some went to MI, while some stayed in Canada. As far as I have been able to ascertain, only one family kept the Botquin name and one of them lives in Montreal.
I have a record of all the families until Andre, Joseph and Jacob, sons of Joseph (which was used a lot in the family along with Pierre). The three of them came to Lousisana with Gen. St. Benet and helped settle the olders Fort in the Louisiana Purchase in Natchitoches Parish, LA
The name St. Andre has also been used as St. Andrie, St. Andria and St. Andry. If anyone would send me a postal address, I would send you the information I have. It covers 258 pages, and some of it pertains to living persons that I can not send via e-mail.