I suppose but again if the ecu was bad it wouldn't matter if the harness and sensor were good. Either way an issue would be present immediately.
Also wth they fixed your valvetronic motor before the shaft sensor and THEN decided the ecu and harness were bad, that is against logic for two reasons. Again they KNOW which was the culprit before via a scan and data (shaft sensor or Valvemotor) secondly how is it yor ecu was working fine to tell them the valvetronic motor was bad to start with LOL . I would visit another shop.
Easier to do sensor/wiring first. btw what are they charging you for the harness/wiring?