Multiple issues regarding WP_REST_Request object on a local wp 4.7

First of all when I included `/src/wpcom.php` in my project the `WP_REST_Request` object was already declared by the core installation so I had to comment `//require_once( $base_dir . '/class-wp-rest-request.php' );`

Second when I tried to get a token with the `request_access_token()` I got an error related to the request method because `self::REQUEST_METHOD_POST` is passed in second position in the `WP_REST_Request` object from this repo but passed first in the core `WP_REST_Request` object. You can see the new object here:
https://developer.wordpress.org/reference/classes/wp_rest_request/

Third in order to make the script work I renamed every classes with the prefix WP_REST_ by WP_API_REST_ to avoid conflicts with the core objects but Im not sure this is a suitable solution.

Fourth I also add to replace `WP_Rest_Client` by my new work around object name `WP_API_REST_Client` in `abstract class WP_API_REST_Object`

What do you suggest to do to connect the wordpress.com API with the new core integration of the REST API?