I both love and hate her. Starlight’s intentions are absolutely wrong and changing the timeline is f’d up. However her confidence, attitude and cleverness is really compelling. I love how she just walked inside the castle, has the guts to sit on Twilight’s thrown with her hooves on the table and that smug smile…yeah she’s winning me over.
Applejack stays in Manehatten, changes her name to Applejewel, becomes interested in fashion, gets diamonds cutie mark.
Fluttershy stays on the ground, finds Sweet Apple Acres, starts to help out, eventually becomes a farm pony and gets her Apples cutie mark.
Depressed that her dresses have no sparkle to them, Rarity forcuses instead on her new kitten. This develops into a love of animals in general. Getting her butterflies cutie mark, she eventually starts the Carousel Pet Boutique.
Pinkie Pie becomes a serious rock farmer, getting her rock cutie mark. She becomes focused on expanding the farm, using jewels she found inside a rock to fund her land grab. Eventually she drives one of her sisters away. The sister goes to Ponyville and finds a happy, friendly town, so different from the dour life she left. Getting a job at a bakery, she learns to smile, lightens up and gets balloons for a cutie mark.
Upset that she failed her opportunity, Twilight runs away and over time becomes a travelling performer, the Great and Powerful Twilight.
Dash becomes a deliquent who gets flatly turned down by the Wonderbolts. Ignoring a suggestion that she get some experience as a weather pony, Dash decides she can form her own flying troupe, the Rainbolts. Their stunts are daring, but dangerous. They soon get a bad reputation and the nickname Shadowbolts.
@Sejen
Except I don’t know how it works in either one.
If there is time travel involved, I’m thinking perhaps there will be an alternate timeline (Maybe like 1985A in Back To The Future) where Starlight interrupts the events seen in The Cutie Mark Chronicles or something. Twilight references that episode in the animatic, so that episode could be involved if there is a time travel plot.