Nice dialogue!

I think that the term "barely worth living" is a terrible source of equivocation that underlies a lot of the apparent paradoxicalness. "Barely worth living" can mean that, if you're already alive and don't want to die, your life is almost but not quite horrible enough that you would rather commit suicide than endure. But if you're told that somebody like this exists, it is sad news that you want to hear as little as possible. You may not want to kill them, but you also wouldn't have that child if you were told that was what your child's life would be like. What Parfit postulates should be called, to avoid equivocation, "A life barely worth celebrating" - it's good news and you say "Yay!" but very softly. I'd even argue that this should be a universal standard for all discussions of the Repugnant Conclusion.