As far as Boxing goes: I'm still betting there's something to be found in the Doctor's Lab that will help "encourage" Chris to lose. Either by some compound which lets the player put a subliminal message in her head or something like that.
As far as the sexual harassment, that could honestly be a nice blackmail route for Chris if NT (I refuse to call you Notty, it's too on the nose) decides to go that way. You could use this bet to catch her in the act much like she does with Annie and blackmail her into submitting. Just a theory. Not to mention your sister is the intended victim and might be willing to help you with the honey trap.
Chris is a character of complete double standards. She's like if there was a second female MC playing against you. Only the things she does or says seems to not have as many consequences as what you as the MC get. Not sure if that's what you intended with her
@Nottravis but that's how I see her.