1 - It's either PWM or CAN; there is no Ethernet.
2 - Please use the search function. Although the bulk of the threads regarding Jaguars primarily discuss the advantages of Jaguars over Victors, they do summarize what Jaguars can do under what conditions.
3 - CAN allows you to access the finer functions of Jaguars, specifically closed-loop control using sensor input. See
http://www.ti.com/lit/ug/spmu131b/spmu131b.pdf for more details.