I was caught up in the delight of Sophia being our sister that I overlooked thinking about how most of the rest of the family are going to react to the revelation
Cat will be delighted I'm positive. Sophia was already like her sister, and now they're both committing incest with us.
Liz will be delighted too I'm sure, if not as much. Liz seem to really be into incest kinda like Fiona.
Amy will probably be "well this might as well happen I guess". She won't be against it, but she's already dealing with a lot.
Nana will probably be happy for us and Sophia more than anything else.
Shizuka will probably be really happy, realize she knows we're fucking yet another family member and get turned on.
Asami will probably be happy for us and make a comment about the importance of family and how we're lucky to have such a big one. Cue us reminding her she's part of that huge family
Tanya, like Amy, will probably be similarly "well this might as well happen I guess" to it. Will probably make some wry comment asking if we have any plans on fucking her now too, to which we're answer we already are fucking her