Re: Linking external post and blogs to BP
@boonebgorges and his work may help with both
1. Under BuddyPress, Profile Field Setup, you can add a new field or field group, including text box type fields. As stated on that admin page, “Any fields in the first group will appear on the signup page.” An URL entered will be picked up as a link in the profile’s public view.
While setting up profile fields, have a look at Custom Profile Filters for BuddyPress https://wordpress.org/extend/plugins/custom-profile-filters-for-buddypress/ with which, among other features “Administrators can specify certain profile fields that link to social networking profiles.”
2. See BuddyPress External Group Blogs https://wordpress.org/extend/plugins/external-group-blogs/ with which individual users might include RSS in group and site activity streams even without blogs being enabled. See BP External Activity https://wordpress.org/extend/plugins/bp-external-activity/ for more admin options, or even FeedWordPress https://wordpress.org/extend/plugins/feedwordpress/ for user blogs.