Data migration D7 to Backdrop

Everyone has their own way.  Due to almost always having errors (and then the resultant huge amount of QA) with module methods (Feeds, Backup and Migrate, etc.) we’ve, for the past ~10 years, have used straight PHP code to migrate data between old and new Drupal sites.  In a exceedingly simple outline:

Have old D6 site Build empty new D7 site Move all data from D6 to D7 though PHP/Drupal API calls.

# # #

My questions are:

- Does Backdrop have the same bootstrap setup? [1]

- Does Backdrop have ALL the API calls that D7 has? [2]

- If so, are they exactly the same syntax?

- If not, which are missing?

Thanks, Michael

[1]
define('DRUPAL_ROOT', getcwd()); //set DRUPAL_ROOT for Drupal
require_once './includes/bootstrap.inc'; //require the bootstrap include
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL); //Load Drupal (loads everything, but doesn't render anything)

[2]
$user = user_load(2);
node_delete($NodeD6→nid);
$newNode = new stdClass();
  $newNode->uid         = $user->uid;
  $newNode->title       = $NodeD6->title;
  $newNode->status      = $NodeD6->status; //(1 or 0): published or not
  $newNode->comment     = 1; // $NodeD6->comment; // 0 = comments disabled, 1 = read only, 2 = read/write
  $newNode->promote     = 0;
  $newNode->uid         = $user->uid;
  $newNode->title       = $NodeD6->title;
  $newNode->status      = $NodeD6->status; //(1 or 0): published or not
  $newNode->comment     = 1; // $NodeD6->comment; // 0 = comments disabled, 1 = read only, 2 = read/write
  $newNode->promote     = 0;
  $newNode->sticky      = 0; // no blog(s) or mass contact should be sticky
  $newNode->nid         = $NodeD6->nid;
  $newNode->type        = 'blog_fast_track';
  $newNode->language    = 'en';
  $newNode->created     = $NodeD6->created;
  $newNode->changed     = $NodeD6->changed;
  $newNode->body['und'][0]['value']                    = $NodeD6->body;
  $newNode->body['und'][0]['summary']                  = text_summary($NodeD6->body);
  $newNode->body['und'][0]['format']                   = 'wysiwyg';

  if ( is_object($NodeD6->taxonomy) ) {
    foreach ($NodeD6->taxonomy as $taxobj) {
      $TidtoUse = map_check_and_create_taxonomy_term($taxobj->name);
      if ( ! $TidtoUse == "" ) {
        if ( $newNode->field_tags['und'][$TidtoUse]['tid'] == "" ) {
          $newNode->field_tags['und'][$TidtoUse]['tid']           = $TidtoUse;
        }
      }
    }
  }

  if ( ! $NodeD6->field_image[0]->filename == "" ) {
    $rowimg = 0;
    foreach ($NodeD6->field_image as $imgobj) {
      $file_to_save = $D6_base_path . '/' . $imgobj->filepath;
      $file_contents  = file_get_contents($file_to_save);
      $file_sch_loc = file_default_scheme() . '://' . $imgobj->filename;
      $file_temp = file_save_data($file_contents, $file_sch_loc, FILE_EXISTS_REPLACE);
      $newNode->field_image_fast_track['und'][$rowimg] = (array) $file_temp;
      $rowimg++;
    }
  }

  $newNode->is_new      = TRUE;
  return $newNode;
etc.