I don't know if the bedding leak is true, but even if its fake the three girls all have that "Offbrand" charm so heres some fanart.

The earthpony strikes me as the potential main character, her cutie mark is three shooting starts and currently she has two friends. Maybe an homage to Twilight's cutie mark being a star surrounded by five stars. I wouldn't mind main characters going forward to have star marks with smaller stars to symbolize their friends.

The unicorn may have the gradient hair, but i think shes not the main character. I also like to think shes not just "the fashion pony", i have no problem if she can sew but her mark can be more then just "purple rarity". I personally think that she might have a knack for empathy and helping ponies who might need a pick me up. I also think that it would be cute if she made plushies, and gave them away to make ponies happy.

The Pegasus is a Theater Kid, there's no way shes not theatrical and doesn't absolutely adore musicals. The head piece also makes me think of Greece, and Greek theater. If she isn't part of a company, or just does acting i will be very disappointed. I like to think that if something is mildly inconvenient she might break out into a "DO YOU HEAR THE PONIES SING!" as a joke once in a while.