From what I can tell, nothing here affects their legal dispute with Epic. They aren't opening up third party app stores which escape the 30% cut.

Facebook joined in after Epic and talked about how it made their one on one feature for tutoring/guitar lessons/etc. infeasible. This seems targeted at allowing that, with the one to many restriction still asking for 30% of school tuitions if they have a remote classroom app and offer payments through the app, or refuse to offer in app purchases of tuition for a free app.

Facebook's action wouldn't effect Epic and vice-versa. The two are unconnected outside the fact that they relate to the App Store.

It was connected in that they were together in time:

> Facebook’s complaints come a day after Epic Games Inc., the creator of Fortnite, sued Apple and Google after both companies removed Fortnite from their respective app stores over a payment dispute.

https://www.washingtonpost.com/business/on-small-business/fa...

Both were obviously also timed to go near the antitrust scrutiny.