I want to leave a prediction here and come back in the future to see how wrong I was
Vanguard: This one is tricky, it can go any way, but I think Ritsu is going to lose in the end.
Second Guard: Here honestly I can't see Shiori losing in any way.
Stalwart: This one is tricky, most people think Michiru is going to win, me included, but if my prediction that Ritsu loses becomes true then Koyuki has a real chance to win, but most likely Michiru wins this.
Vice Captain: This one is also 50/50, but if we want a captain fight and everything goes according to what I am saying, then Tsumigi wins.
Captain: This one is in my opinion the easiest to predict, Mimi will lose, there is no way she is wining this.
As for who leaves after this, its either Koyuki (this is not even a prediction, the plot is going towards that lol) or Michiru.