For whatever reason, my mind is stuck on the note- it seems like it could be leftover "silent" fight between Faith and her roommate. Like one girl wrote the first part (insinuating she's not stupid, she knows what the other is up to- as in jealousy- I know you're hitting on SO and so...) and the other parts are either a response or back and forth. I could see 2 girls fighting like this around someone they don't want to know they are fighting over them- like if he was in the car or same room as them at the time.
I also sense the roommate wanted to leave the club because she was mad at Faith because of jealousy. After leaving, roommate is outside surrounded by males while Faith waits on a bench. It just seems so much like arguments I've seen so often where the jealous girl bullies the one she's jealous of to get her to step away from the attention of males, leaving her feeling frustrated and confused.
I think the last texts Faith made were possibly to prove to roommate that she's helping HER get the guy, to prove Faith isn't trying to get him for herself.
This are some of my gut feelings from reading every post, I hope it makes sense! I think a very jealous female went into a rage, took one or two swings with the bottle which rendered Faith immobile, then found someone with legal know- how to help stage the scene.
My opinion only!
ETA: I think the jealous female left the note there because she had been steaming over this argument and did it to have the "last word"