@valorzard No, I am not part of the Working Group. As far as I know, becoming a member is quite difficult, as you need to represent an organization.
There is also a Community Group where anyone can participate, but my attempts to contribute to its discussions were not productive, most of the time my comments were ignored or dismissed. So I am highly skeptical about the whole thing, and will continue publishing my work to FEP repository.
If I succeed in building a usable FE-ae97 client (the one with client side signing), and then find enough like-minded developers, we can try to push the extended variant of ActivityPub through IETF.