Hi,
1) Yes, that's the reward you can set for an affiliate. You can consider the word fee as affiliate reward/earning in HikaShop. You can also set global fees in the configuration under the tab affiliate. These global fees will be used for all affiliates unless custom fees are set for the affiliate who forwarded the user to your website.
2) Currently, they can just look at the amount they earned as well as a detailed per order, per lead or per click listing of their earnings. You can then create a coupon for them and mark the orders/lead/clicks earnings as paid, if they want to spend their earnings on your website. We can always add an option to convert the earnings into a coupon or something like that. Nothing is frozen, we just need users to tell us what they want
3) I invite you to read our documentation on the affiliate system which explains all that:
www.hikashop.com/support/documentation/54.html#affiliate
Basically, when a user come to your website with the &partner_id in the url, a cookie is added to his browser for a period you can set in the config. This cookie will tell HikaShop later on who is the affiliate who brought the user to the website. As long as the cookie doesn't expire, the affiliate will be rewarded.