Affiliate Role and Credit

1) Affiliate Role Management
When an affiliate registers – it’s created as WP Role: Subscriber.
Shouldn’t / how can we have a different role like: Affiliate?
(it’s important for admin to able to separate regular subscriber users from Affiliate….. Plus if want to email affiliates only…so we can send different emails, then Subscribers.
How can we do that?
Any Idea, Help, Advise …..appreciated.

2) Offline Affiliate Credit.
When an affiliate makes a sale, (membership sale), but a client comes to the site without the affiliate’s link……
How can we handle this issue to credit the affiliate?
..Maybe like a so customer have to select the Affiliate’s Name from a list…..so then that affiliate would get a credit?
How can we do that?
Any Idea, Help, Advise …..appreciated.

Thanks