Hi Shaun,
Was searching the Community Boards for an answer to a different but related question and came across your post.
Not sure if you ever figured this out, but, if not, the DraftOrder resource has a property called order_id; posted a screenshot of the property def from the Admin REST API documentation (https://shopify.dev/api/admin-rest/2022-01/resources/draftorder).
Hope this helps get you pointed in the right direction.
