wordpress.org disallowing my plugin becuase of loading core files in cron cpanel file

I think that is the wrong way. What you might consider to to is to create an wp_schedule_event and then run http://www.abc.de/wp-cron.php per cPanel-Cron, that should work and will be a better way in the “idea” of WordPress.

-Edit-

Create an cron.php (or whatever you would like to call that file) in you plugin. Than from the main php file include that cron.php file.

if (wp_next_scheduled('myActionRunCron') === FALSE) {
    wp_schedule_event(time(), 'hourly', 'myActionRunCron');
}

And then register an Action-Handler to that Action myActionRunCron

add_action(
    'myActionRunCron',
    'myCronAction'
);

And in the cron.php-File, place an function named myCronAction. Thats it.

function myCronAction() {
    // do some stuff
}

Than this Action will be run through WP each Hour. You can modify that by modify the wp_schedule_event-Call.

How to configure the Cronjob in cPanel could be found here on Hostgator