Moving wp-config.php out of public_html is mentioned on that page, section 9. I think renaming the wp-admin would probably break more than it protects.
Don't get me wrong, I love WordPress. And I can't stand Joomla. But Joomla works completely off relative URL's so it doesn't have to know it's location. The links work no matter what domain you put it on. You can access the CMS through example.com/~myusername/domains/joomladomain/ or myusername.example.com/domains/joomladomain/ or joomladomain.com/ and it will for fine every way. Which means SSL will work without a dedicated IP address. This would be awesome.
Not sure on the second question.