I imagine in a humanified high school-set FiM, Rainbow is the crazy athletic one (maybe a free-runner?) who dreams of being on the school co-ed soccer team, the Wonderbolts and eventually playing pro. Twilight was transferred in from a private school for the gifted because her tutor, Professor Celestia, was worried that she was developing too much of an insular personality and needed to learn to socialise.



Twilight is always after Rainbow to try to keep up her grades, never tiring of reminding her that if her average is too low, the Wonderbolts won't even let her try out.



Hmm... What about the others? Rarity is the head cheerleader and is always trying to convince Twilight, Fluttershy and Applejack to join the squad. Fluttershy is the quiet one who all the boys moon over because she is so pretty and nearly made the jump to stardom after she was the model for Rarity's end-of-semester fashion show. Pinkie Pie meanwhile is still the high-metabolism crazy party-lover who is always trying to make friends with everyone. Applejack is an orphan and is permanently on the verge of having to drop out to help her big brother with the family farm and looking after her kid sister. The others help out whenever they can because... hey! What are friends for? Spike is Twilight's adoptive younger brother and hangs out with the Crusaders (all just-joined Middle School) in this universe. He still has a crush on Rarity and helps out Twilight as her invaluable sanity checker.



Overall, they are a weird group but they seem to mesh together well. The other kids of Ponyville High, noting that they are the tightest of friends and stronger together than apart call them The Elements of Harmony. Rarity, in a moment of madness, even created 'uniform' hoodies for them with the 'Elements of Harmony' name on the back.



They became famous in the town after staging an intervention that persuaded Professor Celestia's younger sister, Luna, to give up her biker life and return home; it's something that the gang's co-leaders, two ne'er-do-wells called Discord and Chrysalis, have neither forgiven nor forgotten.



In terms of the secondary characters? Ditzy is an older girl who had to drop out after she got pregnant and now works as a bicycle courier to support her little girl. Lyra and Bonbon are the "out and proud" couple of the county - Lyra is a violinist in a classical band led by Pinkie's cousin, Octavia, while Bonbon works in a sweet shop that's the cheerful rival of the malt shop where Pinkie works on weekends.



The Crusaders are four middle-school kids: Rarity's kid sister Sweetie, Applejack's younger sister Applebloom and Fluttershy's cousin Scootaloo, who are all determined to get to match their older kin's fame. Spike has started hanging out with them lately, mostly because he knows them best thanks to Twilight's friendship with said older kin.



Yeah, they're really just ordinary kids...



Until the powers started to manifest in them.