Pass list from Jquery to form
For anyone looking to an answer to this, it really depends on whether or not you're working with an AJAX form or not. Ideally I wanted to avoid just populating a text area with my updated field to be submitted, so thankfully, since it was using the AJAX form, I was able to pass it information dynamically through Jquery. 

In your javascript

// whatever your function is to get the information you want to pass
....
Drupal.ajax['edit-save'].options.data._my_vars = JSON.stringify(myList);

// Where 'edit-save' is the ID of my save button in my form
// you can console.log(Drupal.ajax) to see what options you have


Then in the callback for your AJAX request, the return request is stored in

$form_state['input']['_my_vars'] // or whatever variable name you passed above


Then you can check whether or not the response has comeback empty by using

 if (empty(json_decode($form_state['input']['_my_vars']))) {
   form_set_error('save'); // You can set the error to be any form element
 }


and in your callback code you can make your own error handling by doing

if (form_get_error() !== null) { 
  // fail code
} else {
  // success code
}


Hope this helps someone else down the line