Using ajax in my entityform
The ajax from a form is handled by the form function itself wich is edited in the mdule layer, not in the template layer. The custom module approach would be. 

Find the id of the entity form, see this Tutorial

Once you have the id you can use the MY_MODULE_form_FORM_ID_alter to edit the form elements to use ajax.
See this Tutorial for more info on ajax forms. 

If you want the ajax callback to alter an external element/several wrappers you can use the ajax_command_* functions to change pretty much anything selectable by JS. 
Have the ajax callback return something like this. (you won't need to set the #ajax wrapper in this case). 

More about the drupal's ajax_command_* functions

function AJAX_CALLBACK_CALLED_FROM_FIELD($form, &amp;$form_state){
  $commands[] = ajax_command_html('JQUERY_SELECTOR', 'VALID_HTML'); // Or any other valid ajax command. 
  return array( 
    '#type' =&gt; 'ajax', 
    '#commands' =&gt; $commands
  ); 
}