Hi @liza_s,
with the rest API you can only recive the information that you can find into the documentation.
A “workaround” to retrive additional informations is calling a workflow via API. You can create a custom workflow where you read all the info that you need and it send via email or you can save a file in a FTP for example, and later you can call this WF via API.
An other way is modify the API of IIQ, but I never tried.