Send an agreement via a workflow with the REST API

Here are some notes that I took on what I've discovered to get workflow sending to function. These aren't described anywhere else, so hopefully these help someone besides myself.

• MISSING_REQUIRED_TO_FIELD: the "name" in each "recipientsListInfos" object can be found by making a proper API call to get the workflow by ID, and checking the "recipientsListInfo". Each object contains a "name". (you can also check CCs this way) An incorrect name will result in the error. Note that the names are case sensitive and numerical order might be confusing. If a recipient is marked as "editable": false, I don't think you can override it with an API call, you must make it editable in the workflow designer.
• INVALID_TRANSIENTDOCUMENT_ID: The document(s) must already be added to the workflow in the workflow designer. The document "name" required in the "fileInfos" object can be found by making a proper API call to get the workflow by ID, and checking the fileInfos for the document you want to send with the workflow. Do not specify this as a transient ID, instead as a workflowLibraryDocumentId.
• If you do not specify a "name" you will get a FILE_INFO_NAME_MISSING error.
• ALL files marked as required in the workflow designer or otherwise MUST BE DEFINED in the fileInfos.
• If you specify an incorrect "fileInfos" "name", it will succeed, but you will get an error message email.
• MISC_ERROR: in my case this was caused by a field being marked as required in the workflow designer "Sender Input Fields" tab and I did not merge a value into it with the "mergeFieldInfo" parameter (even though the field had a default value specified).
• Also note that in the workflow designer, one can only specify 10 input fields as required, why? What if everything is required?

It seems that there is a lot of work that needs to go into to the workflow designer as well as making the actual API call, but it's not really outlined anywhere...