Hello Joost,
1. The solution will be to edit the "Preload version" of your email and add that kind of code at the end :
if(isset($data->order_created))
$vars['ORDER_DATE'] = date('m.d.y H:i:s',$data->order_created);
And then display the order creation date through the "HTML version" by using the following code :
2. For the user email, you'll find the "User id" through the "$data->order_user_id" variable, so you'll just have to retrieve your user email and then display it like I showed you through the point 1.