Hi Jason, it looks like the only problem is that we are registering our calendar plugin with the same name as the default WordPress calendar widget. To remedy this you could follow the tutorial I wrote up on completely customizing widgets: https://theeventscalendar.com/how-to-completely-customize-widgets/
You’ll want to unregister the calendar widget loaded by our plugin in /wp-content/plugins/events-calendar-pro/lib/widget-calendar.class.php – and then register your own and modify the name on line 25 of the above file to something like this:
$this->WP_Widget('events-calendar', __('Events Calendar'), $widget_ops);
I hope that helps!