I'm a little uncomfortable with the degree of consequentialism here. Not because consequentialism is wrong--ultimately, nothing else can be right--but because it is very hard to evaluate consequences. Thus, virtue ethics, pragmatically, tends to lead to better consequences than consequentialism (where all manner of bias can easily run rampant).

In this light, your claim that we should admit people to personhood based not on verifiable objective measures like "awareness", but on whether it incidentally seems to make us act better in other ways, is suspect.

The same line of reasoning can be used to shut down free speech (because it is true that speech can be used to foster harms, and it is not at all hard to demonstrate it); can be used to forbid depiction of the Prophet (because it diminishes the degree to which he is viewed as sacred, and people do measurably act better when they think about the sacred than when not, at least in certain cases); if declaring cute pictures of anime cats "persons" would lead us to treat each other better, then cute pictures of anime cats would become persons; and so on.

So though it's an interesting approach--one I haven't seen before at least--I don't think it's a very successful one. It does work on things other than humans, but I don't think it's well-established what right and wrong answers for non-human-personhood is. So it seems to me a mistake to entangle abortion rights with this unnecessarily difficult and unresolved question.

Instead, going back to more basic questions: "does it have experiences? is it one of us?" seems a more promising way forward. (Unabashedly speciesist, admittedly, but far more solidly grounded.)