Yes, you can designate another person as your Affiliate Member, although usually this is a family member. If you friend is OK being your 9th Cousin sixteen times removed, I guess that is close enough!
No you cannot bring any car to DE. IDS yes (which your “Cousin” would have to take first) but not DE. For DE it must be a Porsche, especially in the Instructed groups.
Porsche Club of America, Upper Canada Region