Also, here are some first attempts at descriptions for the cell phone for the Main 6, Sunset Shimmer and Trixie (because why not). Since we don't yet know what the others' stories are gonna be, I made them kind of open-ended, but they should at least serve as placeholders.
Applejack
A true blue cowgirl: honest, hardworking, and stubborn as a mule. Her family owns Sweet Apple Acres, and she's been helping out with the farm since she could walk.
Fluttershy
An animal lover who volunteers at the local shelter. As sweet and kind as she is shy, and she's very, very shy. Worries a lot about the shelter, which is going through hard times.
Pinkie Pie
A living, breathing sugar rush, Pinkie never runs out of energy, jokes or sweets, and shares all of them with everyone, whether they ask or not. Making people happy is her mission in life, and she'll throw a party for someone for just about any occasion.
Rainbow Dash
The ace of just about every sports team in the school, and as much a jock as that implies. You'll never find a more loyal friend, though, even if she sometimes makes things worse trying to help you out.
Rarity
The most fashionable girl in school who doesn't follow the trends, she makes them. Literally; she dreams of being a designer. Only a tiny bit stuck up, and very generous to those in need of her help, especially tips on style.
Sunset Shimmer
The former "queen" of Canterlot High, who ruled through bullying and blackmail. Apparently had a change of heart, though a lot of students aren't buying it. Worried she'll never move past her bad decisions.
Trixie
That's "The Great and Powerful Trixie" to you! A self-proclaimed (stage) magician who's about 20% actual talent, 80% ego. More than a little miffed that she's been left out of all the "real" magic going around lately.
Twilight Sparkle
Canterlot High's resident bookworm. Still new to the whole "social life and friends" thing. Studious and diligent to the point of obsession.