Easy: the fandom dies (and then the show dies)
Every guess is based solely on how people think the story SHOULD play out based on how they think the story HAS played out. But fan perception of story differs wildly from how A and E are writing it. Everyone can point to a boatload of evidence of why it can’t be A” but should be “B” but that’s all conjecture based on how you feel about A and B’s overall importance.
Every piece of evidence needs to come with the caveat of “but I really don’t know because there is no way to know for sure.”
I have seen every theory under the sun for people from Hook to Regina to Neal to Charming to Henry. All of them make some amount of sense. And all of them also make no sense.
So whoever actually dies on SCREEN, I am only predicting this: this is more or less singling the death toll for ONCE. I can’t fathom any logical reason to kill any of these characters. Graham was killed to A) show how far Regina would go to keep the Curse intact and B) demonstrate just what you could loose by breaking the curse.