Both the books you reference are in the Wisconsin State Historical Society Library in Madison, Wisconsin. Some of the facts seem inaccurate, however the majority coincide with my own research on this family. My great grandmother is from the Wisconsin branch of the LaFollette's: Josephine LaFollette(married name Siebecker), she was the sister of Senator and Governor of Wisconsin....Robert Marion LaFollette Sr., a son of Josiah LaFolllette and his wife Mary Ferguson Buchanan LaFollette.
The LaFollette's were wide spread however probably all go back to Jean.
Any information you could share would be useful.
Thanking you in advance,
Judy Siebecker Cantu