make query more simplest and in one query

You can try this

<?php 

    $args=  array(
            "post_type" => array("product", "post", "page"), 
             "cat" => '-124,-52', 
             "meta_query" => array(
               array(
                "key"     => 'include_newsletter_feed',
                'value'   => "",
                'compare' => '!='
                   ),
              ),

         ); 
      $wp_query = new WP_Query($args);
     ?>