How to display author meta and count numbers for each user in comment.php?

Getting user’s metas values :

$user_meta = get_user_meta($user_id, 'YOUR_META_KEY', TRUE); //You have to set the $user_id / And the "YOUR_META_KEY" can be description, name, custom meta...

To get user’s comments count

function commentCount($userId = null) {
    global $wpdb;

    if($userId == null) return 0;

    $count = $wpdb->get_var('
             SELECT COUNT(comment_ID) 
             FROM ' . $wpdb->comments. ' 
             WHERE user_id = "' . $userId . '"');
    return (int)$count;
}

Finally, to get user’s posts count

$user_post_count = count_user_posts( $userId , 'post' );