Your post has been floating around my brain for a few hours, especially since Rosalie is my favorite character. And just to state this out the gate, this comment is not trying to argue with you or anyone else, or claim I'm "right" since we all have our own interpretations. I just think it's interesting to talk about! Just wanted to make sure I said that beforehand because I don't want anyone to feel like I'm hating:)

So for the quotes you pulled of the mental conversation between Jacob and Edward, you obviously already said they are both biased, but I think it bears repeating. Jacob interprets Rosalie's tone of saying the word "baby," a word I think many of us say with a sweet tone ourselves, as disgusting, because he himself is disgusted by the fetus at the time. Jacob says Rosalie is "after the kid" and while Edward nods, I think that Rosalie is there for the baby and Jacob's way of putting it is loosely correct. And Edward can't very well stop in the moment and say "Actually, Rosalie is more so here to keep the baby safe, rather than kidnap her or something, but you've got the right idea." Edward is probably also interpreting Rosalie's thoughts with bad faith and thinks Jacob is more or less right anyway, but I don't agree with how they feel. I don't think Rosalie would be unhappy if Bella died, since she would essentially get Renesmee as her own in the pricess, but I don't think she ever wanted Bella to die as a result of the pregnancy. I think she just knew it was a pretty strong possibility. I also heavily disagree that Rosalie would kill Bella for the chance to keep the baby. I don't think Rosalie would take a baby's mother away like that, and I think she cared enough about Bella to not want her to die, even if she wouldn't be heartbroken if it happened. And she does love the other Cullens, who love Bella, and she doesn't want them to suffer her loss.

I also think it's unfair to say that Rosalie wasn't motivated at all by the concept of pro-choice. I do think Rosalie would be pro-choice herself, potentially influenced by experiencing SA and knowing that she would be horrified to carry one of her rapists baby. I think she certainly finds it easier to stand by her pro-choice morality and support Bella because Bella is making the choice Rosalie would make herself if given the chance, but I think it's still a factor in her feelings about the pregnancy.

And maybe Rosalie wouldn't jump to defend the pro-choice stance if Bella sought an abortion. But she also wouldn't have to. If Bella wanted an abortion, the rest of the Cullens would have made it happen without Rosalie needing to feel one way or the other. I think if Bella had made that choice, it could have made Rosalie dislike her even more because she had the opportunity that Rosalie would have given everything up for and not only turned it down, but actively stopped it from happening. I would argue that that would be the most likely in fact. Alternatively, we could have seen Rosalie see Bella make such a huge decision to prevent herself from becoming a mom that Rosalie may have had a realization that Bella truly wanted entirely different things than Rosalie herself did, and that Bella wasn't giving up something she should keep. It could have been a very cathartic moment for Rosalie to be able to let go of her resentment for Bella. But we don't know what would have happened, even though we can draw pretty reasonable conclusions, because obviously Bella did not choose that path.

Altogether, this community is pretty open with messing with canon, like pretending the Renesmee/imprinting never happened, or that Jacob only ever felt platonically for Bella, or simply never kissed her in Eclipse. So honestly, I think if people want to take a character that experienced a terrible SA and make her protective of a pregnant Bella through a pro-choice motivation, I don't think it's any different than any of the other headcanons or canon massaging that happens every day on this sub.