Add sort option to authors box

Currently when using the shortcode authors box one can only choose to sort by post caount or author name, beginning with the first name.

I would like to add the option to sort by “last name – first name’.

Also, using the pods plugin I have created two extra checkbox areas for the users page,
where one can select if they are “active/non active” members and what type of function they have “photographer/author”.
If possible I would like to add those sort options to the authors box as well.

in includes/td_config.php I come across these lines of text, but where do they refer to ? As I guess that there’s where I need to add the extra lines of code before I can add any additional option in the array below.

array(
"param_name" => "sort",
"type" => "dropdown",
"value" => array('- Sort by name -' => '', 'Sort by post count' => 'post_count'),
"heading" => 'Sort authors by:',
"description" => "",
"holder" => "div",
"class" => "tdc-dropdown-big",
),

any advice is greatly appreciated