I don’t know what content you want to insert in your archive page, but you can always use the file “archive-friends.php” as you can see in the Template Hierarchy to loop your “friends” post type.
Then, to customize the SEO, I recommend you the plugin WordPress SEO by Yoast because it has a strong compatibility with custom post types, so that you will be able to define your SEO description and titles for your “friends”.