It means that it is visible in the deck, but its not actually in the village. So lets say Baa adds Doppelganger to the deck view, but the Doppelganger is not actually in play.
I agree it is poorly written, I will reword that for sure or redesign his ability a little bit.
i believe by "fake" it means that Outcast will appear in the deck, but will never actually spawn. So a fake Doppelganger would mean it looks like Doppelganger has a chance to spawn, but it never will (and you don't know that)
