Draft orders are orders exclusively created in the backend and not by customers hence cannot be displayed as part of the Order object being fetched. All good on your end!
Why don't you just mark the order with a "Payment on Delivery" option? Your order will be created and it will be marked as pending in the payment status, when the customer receives the order you mark it as paid. That way your customer sees his order and you don't have to keep track of drafts.
really appreciate the thought... quick question... can the customer then still pay via credit card and I capture payment through Shopify? or do I have to manage payments outside of Shopify manually?
and where would I 'find' the option of 'payment on delivery'? or is this just a note I'll add to my order and then follow up with the customer?
Once an order is done a Payment status will be assigned, so if he hasn't paid at the time it will show as Pending.
To add custom payment methods go to "Settings" -> "Payments" -> "Alternative Payment Methods".