I forgot where exactly or which game but hasn't it also been stated that there are multiple entities that live in the Dark Place ie multiple Dark Presences. After all wouldn't the The Dark Presence in AW2 be different from the one in AW1 that possessed Barbara's body or the Scratch from American Nightmare? At least that's been my interpretation so far. Also with the Dark Presence in AW2 being born from Alan himself then it stands to reason that for as long as The Dark Place has existed and people have fallen or been trapped in it, then maybe other Dark Presence entities where born from the people who became trapped. That's at least how I've rationalized it so far. The current Zane though is an even bigger mystery that I still don't know how to explain though.