A question about the choices. I have only 1 playthrough for this game (being a total slut, banging every girl and telling you love them).
I usually start a new game with 2 base files - "All girls" and "None". "All" expected to be no good in the end (unless harem tag) and "None" can be split off into per girl saves as they're introduced. The later is the easiest to avoid being caught cheating.
With NMS I think it's easier to target all girls from the off and then create separate paths after the party for Lizzie/Venessa/Brandy/Amiee/Stephania. You can add Jeane/Nichole/Anastasia/Cecile/Daphne to any of those & save separately and reject the original choice later. You can only get to Amber if you're on a Stephania path though.
Joint paths known to work: Lizzie/Vanessa, Anastasia/Cecile & Brandy/Nichole (until you have to choose either Brandy or Nichole in Ep.10).
Joint path I have but expect to fail in Ep.11: Lizzie/Vanessa/Amiee, Amiee/Jeane, Lizzie/Vanessa/Amiee/Jeane