@ningosi in fact the OCL Subscription module is still very relevant.
The purpose of this project is to create a new UI for OCL so that people can more effectively create their own dictionaries there.
Once they’ve done this, they’ll use the existing module you linked to, to keep in sync.
It was the link. Apparently I needed to log in using my OpenMRS google account to be able to approve people to join. Next time I’ll try to figure out how to not require approval at all. (I just used the default hangout created by google calendars when I created the event, but apparently that doesn’t behave as desired.)