And Helen and Alice are both Scootaloonote Though Martha is also Scootaloo - from the G3 cartoons that is and Apple Bloomnote Starting in season 4 respectively!
In addition to that, their teacher is Princess Celestia and Alice's older brother Ronald is The Great and Powerful Trixie (as well as Queen Chrysalis). Although Ronald's role is also reminiscent of Kevin.
In Finnish, Martha (Katja Sirkiä) is Rainbow Dash, and Queen Elsa of Arendelle. Compare a scene from the episode "Martha the Weather Dog" where Martha imagines the role of weather dog as the weather bringer.note FIM/G4!Rainbow Dash, along with other pegasi, is able to control weather. Queen Elsa, with her magical power, accidentally brought winter in the summer day of Arendelle for once.