I was over at True-Blood.net and Raelle Tucker who writes for True Blood of course and she used to be one of my favorite writers when she was on Supernatural did an interview on their blogtalk radio and she is well aware of ES in the books but cautions that they can't guarantee going the ES route. She also says that they're not a given just because it's in the books. She also mentioned that Deborah (Jessica) made an impression and the writers having Bill and Sookie try to be “parents” to Jessica was “too good to pass up.”