Hi Brian
You did find the most relevant thread for this inquiry. As explained in the other thread, the APIs and related permissions are explicitly designed to treat the role information as privileged and effectively show them on an all-or-nothing basis, under the assumption that only highly privileged users would have access to this information.
Your use case offers a compelling reason to show a subset of the role information to less-privileged users to allow you to filter enrollments based on role in the org unit. The other thread provides some suggestions around creating a Service Account to retrieve and parse this data on behalf of a user, but warns about the potential risks with that approach.
I'll reiterate another suggestion from the other thread - you can log a Feature Request through a Support ticket opened by your institution's Approved Support Contact. Or you can add this feature to the
Product Ideas Exchange. (Note: You have to be a member of the old D2L Community Site in order to access that link.) Be sure to include the details of your use case, since it's a fairly compelling example.
~Sarah-Beth