Using Display Name instead of @username?

// Put Profile User's Email Address in Profile Header
function DisplayedUserEmail() {
global $bp;
echo '<br /><div class="bp_header_email"><a href="mailto:'. $bp->displayed_user->userdata->user_email .'" target="_blank">'. $bp->displayed_user->userdata->user_email .'</a></div>';
}

//add_action( 'bp_before_member_header_meta', 'DisplayedUserEmail' );

// Put Profile User's Display Name at top of profile
function DisplayedUserFullName() {
global $bp;

echo '<h2 class="user-nicenmame bp_header_displayname">'. $bp->displayed_user->fullname. '</h2>';
}
add_action( 'bp_before_member_header', 'DisplayedUserFullName' );

# diff /www/vhosts/example.com/htdocs/wp-content/themes/kleo-child/buddypress/members/single/member-header.php /www/vhosts/example.com/htdocs/wp-content/themes/kleo/buddypress/members/single/member-header.php
24,25d23
< <div>
< <h4 class="user-nicename"><?php echo xprofile_get_field_data('31'); ?><br>
27,36c25,29
< <?php
< global $bp;
< echo '<a href="mailto:'. $bp->displayed_user->userdata->user_email .'" target="_blank">'.$bp->displayed_user->userdata->user_email .'</a>'; ?>
< </h4>
< </div>
<
< <span class="activity">
< <?php if ( bp_is_active( 'activity' ) && bp_activity_do_mentions() ) : ?>
<       @<?php bp_displayed_user_mentionname(); ?>: <?php bp_last_activity( bp_displayed_user_id() ); ?></span>
< <?php endif; ?>
---
>       <?php if ( bp_is_active( 'activity' ) && bp_activity_do_mentions() ) : ?>
>               <h4 class="user-nicename">@<?php bp_displayed_user_mentionname(); ?></h4>
>       <?php endif; ?>
>
>       <span class="activity"><?php bp_last_activity( bp_displayed_user_id() ); ?></span>

<?php

/**
 * BuddyPress - Users Header
 *
 * @package BuddyPress
 * @subpackage bp-legacy
 */

?>

<?php do_action( 'bp_before_member_header' ); ?>

<div id="item-header-avatar" class="rounded">
        <a href="<?php bp_displayed_user_link(); ?>">

                <?php bp_displayed_user_avatar( 'type=full' ); ?>

        </a>
  <?php do_action('bp_member_online_status', bp_displayed_user_id()); ?>
</div><!-- #item-header-avatar -->

<div id="item-header-content" <?php if (isset($_COOKIE['bp-profile-header']) && $_COOKIE['bp-profile-header'] == 'small') {echo 'style="display:none;"';} ?>>
<div>
<h4 class="user-nicename"><?php echo xprofile_get_field_data('31'); ?><br>

<?php
global $bp;
echo '<a href="mailto:'. $bp->displayed_user->userdata->user_email .'" target="_blank">'.$bp->displayed_user->userdata->user_email .'</a>'; ?>
</h4>
</div>

<span class="activity">
<?php if ( bp_is_active( 'activity' ) && bp_activity_do_mentions() ) : ?>
        @<?php bp_displayed_user_mentionname(); ?>: <?php bp_last_activity( bp_displayed_user_id() ); ?></span>
<?php endif; ?>

        <?php do_action( 'bp_before_member_header_meta' ); ?>

        <div id="item-meta">

                <?php if ( bp_is_active( 'activity' ) ) : ?>

                        <div id="latest-update">

                                <?php bp_activity_latest_update( bp_displayed_user_id() ); ?>

                        </div>

                <?php endif; ?>

                <div id="item-buttons">

                        <?php do_action( 'bp_member_header_actions' ); ?>

                </div><!-- #item-buttons -->

                <?php
                /***
                 * If you'd like to show specific profile fields here use:
                 * bp_member_profile_data( 'field=About Me' ); -- Pass the name of the field
                 */
                 do_action( 'bp_profile_header_meta' );

                 ?>

        </div><!-- #item-meta -->

</div><!-- #item-header-content -->

<?php do_action( 'bp_after_member_header' ); ?>

<?php do_action( 'template_notices' ); ?>