Re: Integrating blogs from outside ?
Importing blogs (your second bullet point) is part of WPMU and nothing to do with Buddypress. You can do this by visiting /wp-admin/import.php on your site as an admin user.
The first bullet point is something that at least person is working on, but I don’t expect to see anything released for a long time yet.
I will eat my hat if their isn’t an existing RSS widget for WordPress. Have a look through https://wordpress.org/extend/plugins/.