Well, I've got some good news.
When I get my new laptop, I'll be attempting to import custom models.
That means importing characters from other games or modifying the existing Bully models.
That then means it'll be fully possible to get a all Christy player model over Jimmy, with all hair styles and clothes replaced.
But most likely I'll try importing models from GTA SA first.
As for the quotes, LOADS of Jimmy's quotes were removed. Not to mention regardless how hard you work on replacing all of Jimmy's audio, Christy will still have Jimmy's voice in the cutscenes and don't forget most text will need re-writing and you'll most likely want to replace Zoe. 
I can send you Christy's audio if you want.
Well now that i think of it,I'll try this first,But i spoke to 1emon,He also is trying something. But he seriously got some work done on it. But i have not seen anyone replace the closet clothes with different clothing that isnt jimmy as in the same models instead of switching back to jimmy,And giving us one of their other clothing. So anyways,He even included cheerleading,He replaced the boys dorm arcade game with cheerleading. And FINALLY,What i have been asking for,He has the taunts and compliment! So finally.
