Thanks for the responses.
My own replies/things I learned (in keeping with Alicorn's responses, I will try to phrase this in terms of animals rather than abortion):
1. I hadn't realized that people would draw a distinction between "I want this species to exist" and "I want members of this species to exist." If you prefer the former and don't accept the existence of DNA records, etc. as sufficient, it seems you need at least one member of the species to be instantiated (i.e. alive)--and presumably you need enough to have at least a full social group so the animal is "happy"/"content". Obviously in the world of the story humanity has gotten rid of not just animals used for meat but those used as pets. To me that indicates that humanity has decided collectively that there is no way to raise animals, even pampered as pets, without excluding suffering. So we seem to be in a situation where we've chosen a certain number of animals to suffer to satisfy our values, which although it isn't necessarily incorrect seems problematic. (It's the Omelas thought experiment, but with a payoff that seems much less worth it to me.)
2. I find Kappa's (2a) ("And I'm going to take good care of my dogs, so they won't be suffering all that much anyway.") to be morally abhorrent, much more so than (2) by itself. I think this is because it's special pleading--or, in more philosophical terms, it doesn't universalize. I would find a (2b) ("So I'm going to support placing animals in the habitat that minimizes their suffering as much as possible.") or a (2c) ("So I'm going to advocate for training prospective pet owners in how to minimize their pets' suffering") to be much less upsetting.
3. I definitely understand DeAnno's response (except for how you can possibly take acausal bargains seriously without being a utilitarian; maybe you're calling "explicitly not a utilitarian" is what I'd call "having a selfish utility function"). But I don't think you agree with Clara's position in the way I phrased it, really--you constructed an argument which might actually be closer to Clara's "actual" reasoning but which I find much less interesting philosphically. :p
4. I definitely understand MaggieoftheOwls and DeAnno's (slightly different) points re abortion being different because of an offsetting negative utility to the mother (to phrase it overly technically :p). Obviously this is a hugely important factor, and I think by itself is a winning argument for the pro-choice position. But I would much prefer to abandon the premise that potential lives must have positive utility altogether (c.f. Peter Singer's position on infanticide and Greg Egan et al's position on running simulations with human-level or greater agents in them who aren't aware they're simulated being immoral, both of which I broadly hold and which don't have this negative utility feature to the same extent).