Why do Activities entered via a webform *not* marked as Completed get entered into Civi as completed?
If you use a webform condition (part of Drupal webform 4.x), with a question like 'Did you speak with the target?', you could hide the fields for Activities 2 and 3 if the caller enters 'No'. If the fields are hidden based on the condition, they will not process to CiviCRM.