What would be the best way to setup if you registered the .net .org and
.info of a product's name on clickbank as an affiliate?

Example:
Product website: wwwproductcom

Your websites:wwwproductorg, wwwproductnet and wwwproductinfo?

What would be the best strategy as an affiliate?

Same as if you had one domain IMO.

Content is king as far as search engine rankings go, so I would suggest that you focus on 1 domain and 1 website only, at the end you'll have more content and better rankings.

Agreed. Built a site with the .org, park the .net and build backlinks to the .info and 301 redirect .info to .org site. If the product is becomes hugh then maybe also build a second site with the .net for more traffic.