Yeah, I have done Nakano's bad ends, and in one he just offs you, in other he marries you if you are a girl. Not sure if I would call the latter a bad end, tbh.
yeah, bud, this never happened. Folks have their opinions about the kitsunes, how they treat non-kitsunes, and who you can/can't bang, but their quests have been consistently well liked, from what I can tell.