I think the end of the show was just showing the set. Now, if there were dead bodies scattered around, then perhaps I would have viewed it differently.
Libby was in the church with Hurley.
Yes...I think you are correct. I need to watch the last 30 minutes again...but now I remember Christian's words to Jack about some dying before and some dying long after...by which I think he means Hurley and Ben.
If you look closely, you can see footprints around the wreckage. It was just for ambiance that they showed the wreckage, sort of to show how far the show came. It was a nice touch.