To my mind, the personhood or lack thereof of the foetus really doesn't matter very much, because it's growing in a person whose personhood is indisputable and who doesn't want it to be doing that.
In many situations, we are happy to make one person suffer or die - even if they don't want to - for the good of others. Child support, taxes, any form of imprisonment or execution or corporal punishment, the draft... And as well, those are all cases where the probability of saving a life are all vastly lower than in abortion where you know for certain that the fetus will die.
I don't agree that any of your examples quite work. Imprisonment, execution and corporal punishment follow some behaviour that we agree is wrong, unlike pregnancy. (Personally I disagree with capital punishment and most forms of corporal punishment anyway.) And as for child support and taxes, I think there's a relevant distinction between bodily autonomy and financial autonomy.
A few years ago, I wrote a little dialogue I imagined between 2 materialists, one of whom was for and one against abortion, centering on the personal identity question. I recently cleaned it up and added a number of references for the biological claims.
You can read it at An Abortion Dialogue.
Early feedback from #lesswrong is that it's a 'nicely enjoyable read' and 'quite good'. I hope everyone likes it, even if it doesn't exactly break new philosophical ground.