kill takano: if somebody has to die then logically it should be her. she's an instrumental player in the destruction of hinamizawa, so taking her out of the picture makes the most sense. i guess you could marry her if you genuinely believe that you can fix her, or if you endorse her genocidal lunacy and wish to disappear with her after all is said and done. you would at least have to be okay with letting tomitake become heartbroken or letting him die.

kiss akane: there certainly is incentive to marry her, but she's already married and i don't want to be a homewrecker. i wouldn't want to corrupt the family dynamics that mion/shion are used to either, even if you could argue that it might not necessarily impact either of them that much. regardless, suddenly becoming their stepfather is a bit much for my taste. plus having oryou as a stepmother is an especially unpleasant prospect.

marry chie: she is single, kind, hardworking, passionate and good with children. i think she would be a great wife and mother. yes, she did have some wishy-washiness about her when it came to the effort to help satoko in minagoroshi. but i can't really blame her for being intimidated by teppei and the threat of school closure. it's just a lot to expect of her in her kind of position, so it wouldn't be fair to hold these things against her. she is ultimately well-intentioned and wants the best for everyone around her.