The reason religion is so powerful

[The Architect Of Fate]

I think the reason we would choose an infant over an elderly person (and you hinted at something similar) has something to do with Thomas Nagel's famous argument: Death is evil insofar as it deprives us of life. Therefore, the younger you are the more life you can be deprived of, and the more tragic the death. And abortion, I would argue, logically deprives an organism of the most life possible.

Already countered this 

ps. I hadn't thought about your pregnant vs nonpregnant scenario before, and I think it's a question that reinforces my object permanence argument: a pregnant woman can be visualized in a way that an embryo cannot. Therefore, I suspect that someone who would be fine with a two-month abortion on paper would nevertheless be inclined to save a woman that is pregnant over her twin sister that is not.

No, it really doesn't

And again there is that lack of character agency.