Is the MSPFA just a general archive, like Ao3? Does it host any work uploaded to it? Is there not, like... An approvals process with checking the works posted? I assumed it functioned more like FRAF, where you have to be approved, is it more of an open site where anyone can post anything?

Yeah, it's a general archive. It has an associated discord but it's not that unpleasant or hostile; those screens probably came from Makin's hs discord