"URL: [base]/Patient/$Questionnaire-for-Order

URL: [base]/Patient/[id]/$Questionnaire-for-Order"

This operation can't be executed against the Patient endpoint (or Patient instance endpoint) because the Payer is very unlikely to have either of these.  Also, the convention for operation ids is all lower-case.  The operation should be invokable at type only and should be against the Questionnaire endpoint.

Finally, if we're going to adjust it to support retrieving a package based on a Questionnaire canonical as well as orders + coverage, the name should change.

Recommendation:

[base]/Questionnaire/$questionnaire-package