I can't think of a reality in which anyone would pick Defoe over Cantona. The difference in touch, control, ingenuity, creativity, link play even and range of finishes is startling. There isn't even a difference in goal rates. Defoe only scored more than 13 goals twice for us (4 times in total in his career). Cantona did that in 2 out of his 5 seasons for United and in way fewer games played and was otherwise also way more impactful, in build up, and seizing the moment.
There's no world in which a manager would pick Defoe over Cantona.