As for authority. I think at this point there truly are no authoritative bodies driving the fediverse.
In the 3-stage bottom-up standardization process I discussed at the time at SocialHub, the level of authority was highest at the W3C, lowest at individual FOSS projects, with the FEP process inbetween as a place where good practices and protocol mechanisms bubble up from the ecosystem as good candidates for further standardization.
This process in reality doesn't exist. The connections aren't there. The SWICG operates alone, the FEP does too, and so do all the various independent developers when they invent new things.
In that setup I'd say the SWICG has the same level of authority as the FEP Process does, or any other focal point for collab between fedi devs (e.g. code forges, podcasts). Just another party at the grassroots level figuring out best practices.
https://socialhub.activitypub.rocks/t/3-stage-standards-process-guaranteeing-an-open-and-decentralized-ecosystem/3602/40?u=aschrijver