I found this quote from Stephenie Meyer on imdb:

"I do have a fairly intricate outline for book five. That's not including Midnight Sun, that will be the next one. It isn't told from Bella's point of view, but the characters that you know now will remain characters in the story, so like Alice and Jasper, and we'll still have Edward and Bella around."

So does that mean that both Edward and Bella, and Alice and Jasper make it through alive in Breaking Dawn?!