public function getUser()
{
return $this->hasOne(User::className(),['id'=>'user_id']);
}
public function getUserOrg()
{
return $this->hasOne(UserOrg::className(),['org'=>'id']);
}
$service = Service::findOne($id);
// можно так, меньше запросов к бд:
// $service = Service::find()->with(['User','UserOrg'])->where(['id'=>$id])->one();
echo $service->user->username;
echo $servise->user->userOrg->name;