As was said there is no single ‘pro choice position’. The one above is I personally find more reasonable than what I believe is the much more common, simplified politicized position which does effectively say the fetus has no rights: it’s a ‘lump of cells’. But then later on there can be restrictions, because some judges said so once, and what they said can never be revisited.
And that’s not necessarily because the people (organizations more than individuals) promoting the absolutist pro choice position are necessarily inherently stubborn or unreasonable though I find they often are. The idea that abortion is a question of relative rights of a woman and fetus implies that there can be all kind of abortion limitations, and each one has to be litigated based on how the rights line up in that particular situation, and re-examined continuously as science and other factors change. IOW your idea is reasonable, but a whole lot more complicated than woman 100% rights, fetus 0% rights. Also, I think the pro-choice absolutists have a fairly good argument that RvW and Casey are more compatible with 100/0 than they are with your idea.
So yours is reasonable, and I think many average people across the spectrum from mildly pro choice to mildly pro life agree with it implicitly even if they don’t articulate it. But it’s also a can of worms relative to the more common (in politics at least) absolutist pro-choice position.
Anyway a law which deems it murder to kill somebody else’s fetus under the current RvW ‘right’ of a woman to kill her own fetus is simply a contradiction. I see no reason to bend over backwards trying to come up with arguments how it’s not a contradiction. An absolute/RvW friendly pro-choice position could easily accommodate killing somebody else’s fetus as a crime, but calling it murder is a contradiction to the hardline pro choice view. Your car doesn’t have any rights of its own, smashing the windows is a crime against the owner though the owner smashing them herself is not a crime. But this is being called, by analogy, a crime against the car.