I like your thoughts on Facilier being the Guardian. But there going to have to do quite a bit to explain away his shadiness in the past and present, to where he’s a “good guy” worthy of Regina. I could see something having happened between the evens of 7×12 and now that redeemed him, but then why he is still using Naveen and Regina is still wary of him? I really want Henry to be the guardian, because it fits with prophecy and would tie up “the boy will be your undoing” from Season 2 – it’s always bothered me they never came back to that.
But he was undone by Henry, just not in the way he thought. Henry lead him to Pan and the only way to get rid of Pan was to kill both himself and Pan together with the dagger.