UserName Exposed…

This question is for Security.
How can I display nickname only instead username in links?

I found this functions.php:

add_filter( 'request', 'wpse5742_request' );
function wpse5742_request( $query_vars )
{
    if ( array_key_exists( 'author_name', $query_vars ) ) {
        global $wpdb;
        $author_id = $wpdb->get_var( $wpdb->prepare( "SELECT user_id FROM {$wpdb->usermeta} WHERE meta_key='nickname' AND meta_value = %s", $query_vars['author_name'] ) );
        if ( $author_id ) {
            $query_vars['author'] = $author_id;
            unset( $query_vars['author_name'] );    
        }
    }
    return $query_vars;
}

add_filter( 'author_link', 'wpse5742_author_link', 10, 3 );
function wpse5742_author_link( $link, $author_id, $author_nicename )
{
    $author_nickname = get_user_meta( $author_id, 'nickname', true );
    if ( $author_nickname ) {
        $link = str_replace( $author_nicename, $author_nickname, $link );
    }
    return $link;
}

It works, but only with Blog Posts, not in:

Comments, meta, widgets, etc.
Neither for: buddypress (activity, groups, members, notifications, etc.) and bbpress forums.

If you Right Click on Public Name you can see the Username in:

http://www.yoursite.com/author/username (in Comments)
http://www.yoursite.com/members/username
http://www.yoursite.com/forums/profile/username

Also, If you go to a Buddypress Profile, you can see, for example:

John Doe
@johnstack (username)

==========================

The correct:

John Doe
@johndoe (nickname)

http://www.yoursite.com/author/nickname
http://www.yoursite.com/members/nickname
http://www.yoursite.com/forums/profile/nickname

Please, any solution for Forcing to Show the Nickname Only (based on your first name and last name) in Profile and all Links.