This may not be needed if this idea is delivered: 

In the absence of an out-of-the-box way to create topics anonymously, it’d be possible to set up a custom automation with a survey or another intake form that generates the topic as a set anonymous user. 

The API operations needed for creating the anonymous question are already available. However, we’re missing a key piece for a positive user experience: the ability to subscribe the user to the topic so they receive updates on their (anonymous) post. 

Operations exist for assigning a Like, but not for subscribing. 

Subscribing is preference as it is also anonymous and because it would then leverage system emails and user preferences.