How to display items in Rules data selector in alphabetical order
This is not an answer in any way, but

on around line 150 of rules.autocomplete.js, there is this code..

  Drupal.rules.autocomplete.prototype.success = function(data, request, response) {
    var list = new Array();
    jQuery.each(data, function(index, value) {
      list.push( {
        label: value,
        value: index
      });
    });

    this.cache[request.term] = list;
    response(list);
  };


That could possibly be where you need to add some code to rearrange the list. It might be there or it might be elsewhere.. It's a huge module.

If you manage it, create a patch for yourself that can be applied each time the module is updated.