How do I get the facbook comments in a tab next to the native comments?

This can be marked as resolved, I'm going to find a different solution (because of an unrelated issue to this). Thanks!

You can use Comments Evolved with wpDiscuz. To make wpDiscuz available in the native comment tab you should make this small change in this plugin /includes/templates/partials/wordpress.php file:

Find this code:

if (file_exists(TEMPLATEPATH . '/comments.php')) {
	include_once TEMPLATEPATH . '/comments.php';
} elseif (file_exists(TEMPLATEPATH . '/includes/comments.php')) {
	include_once TEMPLATEPATH . '/includes/comments.php';
}

Replace to this:

if(file_exists(ABSPATH . 'wp-content/plugins/wpdiscuz/templates/comment/comment-form.php')){
    include_once ABSPATH . 'wp-content/plugins/wpdiscuz/templates/comment/comment-form.php';
}elseif (file_exists(TEMPLATEPATH . '/comments.php')) {
    include_once TEMPLATEPATH . '/comments.php';
} elseif (file_exists(TEMPLATEPATH . '/includes/comments.php')) {
    include_once TEMPLATEPATH . '/includes/comments.php';
}