I have decided to try the game... Which has served to confirm what I suspected, that I should have used my time to do something else.
The sister doesn't interest me at all, as you say she already chose Nate, and I can't find any reason to want to give her a second chance.
Yumiko stops being an LI the moment she cheats on the MC. In fact I haven't passed that point, there I have clearly seen that it wasn't worth continuing with the game.
I don't have a formed opinion of her fake niece... But the fact that she is the daughter of the stepsister that I don't like and Nate... the bottom line is that I'd rather pass of her.
The stepmom is the only one who seems like a good LI.
Neon Berry, thanks for the game, but I'm pretty sure that I'm going to pass.