I really like this rivalry. Certainly better than Cole vs. E.Cole (though literally any match up would be better than that). Definately one of my favorites up there with Dante/Nariko, Cole/Raiden (assuming that is it), and Big Daddy/Sackboy.
My honest opinion? they made the other 9 rvialries and said "huh..al we have left is Evil Cole and Fat Princess...oh well, we will come up with some way to make this interesting.
my best guess for the scenario?..
Evil Cole walks up, sees FP eating obnoxious amounts of cake, then says- "That junk food cant be good for you. id drop it if i were you" in a kind of mocking and annoyed tone.
FP - Come join me, lets have some cake! (or some passive aggesive, pleasant invitation or greeting-
Evil Cole denies it rudely, tells her to just walk away/ leave him lone.
FP walks up, places hand on his shoulder, says "come now, dont be such a downer/meanie.
Evil cole smacks away her hand, flashes lightning from his hand and says "thats it, you asked for ir!"
The abttle continues
Evil Cole: Who are you?
Fat Princess: I'm Fat Princess.
Evil Cole: You call yourself 'Fat Princess'?
Fat Princess: Yes, that way bytches like you don't do it behind my back.
*The battle commences*