The JSON returned by the CMS API does not include the full definition of a multi-reference object. It only returns the ID. This then requires separate API calls for each sub item. I would also expect this work on multiple levels i.e. multiref items which link to multiref items.
My data structure: Books > Chapters > Notes. I would expect to query the Books Collection and have all nested objects returned in a single JSON response.
As emailed @cyberdave