Something to note: Exdeath doesn't die the same as O1-O3. He gets sucked into the void. That hints towards him being the ACTUAL Exdeath and not a simulacrum like the others. Means we might see Neo Exdeath later.

Also how does this tie in with WoD, since Cloud of Darkness is supposed to be the personification of the Void itself. The Rift from FF5 was just a fancy name for the Void, wasn't it?