Stealth Login Page code snippet to add URL filter to logout/password reset. This will need to be added each time the plugin updates - add to plugin.php.

partial-plugin.php

// After all network activate/deactivate sections, before Global Variables

/**
 * Edit the logout/login/lost_password URLs to the new custom URL
 *
 * @since 2.1.0
 * @param $old
 * @param $new
 * @param $url
 * @return array
 */
add_filter('site_url',  'wplogin_filter', 10, 3);
function wplogin_filter( $url, $path, $orig_scheme ) {
  global $custom_url_ending;

    $old  = array( "/(wp-login\.php)/");
    $new  = array( $custom_url_ending );

  return preg_replace( $old, $new, $url, 1);
}

// Additional Global Variables that have since been removed but are needed for the filter - I don't belive the last two are used because of nonce URLs.

$custom_url_ending = "wp-login.php?" . $slp_options['question'] . '=' . $slp_options['answer'];
$custom_logged_out = $custom_url . '?loggedout=true';
$custom_lost_password = $custom_url . '&action=lostpassword';