Re: How will the Ponds depart?
The Guardian actually has an interesting, if unlikely, theory. They seem to believe having Amy regenerate into Jenna Louise Coleman is plausible. I seem to recall an image of The Doctor passing his regeneration mojo into Amy in a Canadian teaser for the Angels episode so you never know.
"Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying."
--Arthur C. Clarke