I'm completely lost on the ending. Okay, they're all dead, and the alt timeline was about them finding each other so they could move on. got that.
So when did they die? In the plain crash? after the plane crash? If it was either, why is Penny at the church with everyone at the end? she wasn't on the plane, and has never been on the island?
what was the point of them leaving the island in the ajiri plane if they were all dead to begin with?