http://website.com/wp-admin/admin.php?page=s2 – Is there a shortcode or workaround in order to theme these options into a page so that users don’t access the admin similar to how Theme My Login handles registration/login pages?
I would really like Registered users to have the Subscription page themed like my site, is this possible?
Yes, it is. There is a small extension to Subscribe2 that delivers exactly this functionality. It is available from Theme Tailors for just $2.