Hi,
BP pages are not ordinary WP pages. BP use the page system to assign a permanent slug, while content stays dynamic. Usual WP pages are static.
BP pages must be unique. This means also without assigned template, model and of course, should be a slug to a page, and not a sub-page. These page are not intended to be published and exist only for internal use. You don’t need to build a menu for register and activation. Normally, these items come up, depending the context (theme, plugins, widgets) and/or the user status.
Related to “activation” and “register” and most of BP components, you need to declare a “page” for each, despite the fact that BP will only use them to insert a template. Registration will receive xprofile fields which are added to the existing WP registration form.
And another template for the Activation stuff, depending the context: activation key, success message and so on.
