Can I have Comments open to specific users only?

You can check for a user role. This should work when you put the code into the template above the call to comments.php:

if ( current_user_can( 'actor' ) ) // or use 'publish_posts'
    add_filter( 'comments_open', '__return_true' );

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)