He can't help it. He loves her & wants her to be happy and if he can contribute to or influence that happiness, that's just bonus. As much as it hurts him, it would hurt him more to know he's adding to her distress. That's why he can't tell her no. Bella can't stop the pull she feels toward Jacob. When Edward left, he became an integral part of her life. At this point, she's not strong enough to let him go -- not with all this other drama going on in her life.
2. Do think Rosalie wants to save Bella or just the baby? Do you feel that Rosalie is sincere that because of Carlisle, they can save Bella?
I think Rose sincerely believes Bella will make it through as a vampire. Edward would know if she didn't truly believe it & would be more pissed off at her. I think Rose really wants to save both -- she knows how it would affect Edward and therefore her family and her life.
3. What ramifications do the coincidences between Jacob and the baby have? Could there be a deeper meaning or connection?
Really, they only manage to confuse Carlisle & Edward more as to the nature of the baby -- and make Jake quite mad. As it turns out, there was a deeper connection but I didn't quite get it at this point. I just wondered if a vampire & human could make a werewolf baby.

4. Do you think Bella is being reasonable or even realistic in her plans for keeping Charlie in her life? Not taking into account later chapters, what were your feelings when you first read about her plans?
At this point, I didn't think it was very reasonable to think about keeping Charlie in her life. I thought she was stringing him along a bit; postponing his agony especially after she started to sound better.
5. After weighing the facts presented by Rosalie about the birth of other babies like this, how do you think they will deliver the baby and do so in the hopes that Bella can survive?
I thought they would wait until Bella & Rose are sure the baby can survive and then perform a C-section of sorts in a controlled environment where they can monitor Bella's condition.