In the pregnancy option, although it may also be that neither of us is pregnant, it was simply to see who ended up, but if that were the case, the truth is, I would go for Elizabeth because of the wait, apart from she feels a lot for the protagonist, but better Caterine , but I would not do it to make guarara, because there would be no reason to have to assure Caterine since she betrayed her husband because she did not pay attention to him, etc. because of work, Caterine already did it, she betrayed him and the attitude that Caterine has, that is, when we get caught or later on the train that he wouldn't mind if we were with his daughter or the scene in the bathhouse where he teases the mother shows that he doesn't mind sharing rather he wants to do it so he doesn't have to hide his relationship with the protagonist and can enjoy at any time.
I'm not saying that Caterine doesn't mind jogging, in fact she wants to have it, that's why the part when she jokes that she's going to have a baby to see her reaction, in conclusion, the husband doesn't pay attention to her because of work, he won't change and Caterine knows this, that is why she has already made the decision to deceive, she is almost assured, but she would have to be careful that the husband does not change, because the main character told her the first time about the deception that he will change the ring for a chain around her neck, she Keep using the ring, you have to be careful and decide why she should choose to get pregnant, why she could take care of the baby for a while, why if you realize when Caterine makes the baby joke, the protagonist was worried and changed his plans to
get a job in the zaibatsu, etc. on the subject of revenge, then I would change it and to continue now imagine that with Elizabeth, that is, almost the end of the game, but with Caterine she could hide if she has a child and cheats on her husband by saying that it is his to give the protagonist time for revenge and ensure a better future for the harem, even if her husband discovered her, she is an adult, she has the mother of the protagonist to help, etc., while with Elizabeth that would be more complicated since she is young, so better if it was Caterine at that time.
Sorry for so much text I wanted to be as detailed as to why make that decision between Elizabeth and Caterine, later I have other opinions about Sheila and Minami about why they would help in the harem but better just there xdxd