1. You could edit tpl_comment.php and show author's email in frontend.
2. In my mind reverse order isn't applicable to tree view because it will be not usable. But if you want this you will need made modification:
1. Open /components/com_jcomments/model/jcomments.php
2. Replace code:
$options['orderBy'] = ($config->get('template_view') == 'tree') ? 'c.parent, c.date ASC' : ('c.date ' . $config->get('comments_order'));
with
$options['orderBy'] = ($config->get('template_view') == 'tree') ? 'c.parent, c.date DESC' : ('c.date ' . $config->get('comments_order'));