Leaker confirmed via Reddit that there are more characters, Ridley was part of the extended version of the Ninka leak so he's one of four survivors at this point. To give some context it basically boils down to someone either guessing Duck Hunt Dog, Bowser Jr and Dark Pit being in the game, or his information was legit and Ridley, Mewtwo, Dixie and Chorus Kids are actually in, all things considered the latter scenario still sounds fairly likely.
Of course even when we finally do get a legit leak Ridley's fate still isn't sealed, it's almost comical at this point.