1. Is it selfish of Bella to ask Edward to sit out the battle, knowing that it will increase the danger to the rest of his family?A little bit selfish. But it's reasonable, really. He kind of had it coming. And he honestly believes that no more danger could come to his family.
2. When Bella asks Edward to sit out the battle for her, he looks into her eyes for a long time. She sees his eyes "tighten with some emotion I couldn't read" before he picks up the phone to call Alice and make the necessary arrangements. What do you think was going through his mind?I think he was trying to see why he wanted him to hang back, then realizing why, and then regretting it.
3. Do Edward and Alice really believe the danger from the newborns is as trivial as they say, or are they trying to make Bella feel better?Both. I think they're trying to convince themselves, but really think it's kind of true. I think they'd say anything to make Bella feel better, so, that point is a little moot.
4. Why do you think Bella feels it’s more like being with the old Jake -- “easy, effortless, as natural as breathing in and out” -- when he is in wolf form?He smiles more. He licked her face in a playful fashion. He is a lot less angsty. He can't say anything that will make either of them angry or uncomfortable. He's just playful and cuddly.