I actually think that the haircuts didn't happen overnight the day after the runway and before the final judging.
I think the final judging was shot only recently, and in the meantime (weeks? months?) the agency gave Brit a haircut, so Molly had to get a haircut too, in order for the whole thing to look more fair or less suspicious. Because Molly's face is a bit chubbier and less defined with the new cut, and it can't be just from the haircut....
I think some time has passed between the last runway walk/shoot and the judging, and in the meantime IMG already started preparing Brit with the new cut etc.
Also, they probably would have shown the new makeover process and all the drama behind it.
I know they tell the girls they would be getting a makeover, but these things can be easily re-shot and edited to the producer's liking.
Anyway, I think the right girl won. She looks great with any haircut, she photographs well, has a good walk, great attitude and she's trying hard.
Molly is a better model for photos, but in everything else she is weaker than Brit, and her body proportions are too athletic. However, she is definitely the best runner-up they could have chosen.