Authenticates users through LDAP.
No. This plugin only supports LDAP bind.
Yes. You can enable SSL connection in the option page.
Yes. You can customize the search filters (user ID and group) in the option page.
This plugin has a built-in debug mode.
WP_DEBUG is enabled in
wp-config.php, it will turn on the notices that some authenticatin information are added on the log entry.
If you don't know how to define the constant, see WordPress document.