As things stand right now...I have a bad feeling. I've been doing some searching on 4chan and 4-5 "leaks" have shown up about KOS-MOS in the past 2 days. People are either impersonating the cat leaker or they are just trying to get people to talk about KOS-MOS. These leaks I have been reading are saying she's gonna be revealed in the direct though. I'm not sure if these new leaks after the cat one makes it less credible but it sure is bizarre there has been tons of KOS-MOS talk on 4chan, gamefaqs, and here. Also, Vergeben and Sabi haven't commented on the cat leak have they?
However, I did find that one of Sabi's people did say there is a list where Crash and Hayabusa were found to be disconfirmed for fighter #5. Interestingly, this guy even says that "No Namco or Capcom characters" were disconfirmed to be fighter #5 on the list.
https://gamefaqs.gamespot.com/boards/234547-super-smash-bros-ultimate/78090321/929183246 Senselessbreak is in the Sabi discord and was verified by gamefaqs users.
If this development is true then fighter #5 imo is KOS-MOS, a tales character, or Jill Valentine from Resident Evil. This person seems to believe it is a tales character but just remember the trademarked icon Namco filed for tales looks nothing like a smash symbol and even uses a book icon which is nowhere to be found in Symphonia. And I think Vesperia was the first entry in tales to start using a book icon as a save. I wont get my hopes up right now but we really need someone credible to tell us if KOS-MOS is even on this list or not.
Oh and Nintendo uploaded a hidden video today right? Plot thickens...