As Bev said - your wife's visa allows her a stay in the US up to 180 days but this is determined at point of entry by the immigration officer. B2 covers vacation, travel, medical treatment and some sporting events/conventions. It specifically excludes education. Worst scenario - . Why does she not jump through the hoops like everyone else and gets her F1?
There were some changes regarding Canadians recently. Have you checked with the Canadian Embassy?
This is not Turkey - other playground, other rules.