Also, I feel like remiss if I didn't say
"Well, it seems like we have some NIEGHSAYERS".
But yeah, always good to know if people have issues with my story. Thanks for being honest.
Honestly, I don't see room to have any other characters be related. From there, we've got Dash nailed down, with only Fluttershy's parentage being a complete mystery.
Fluttershy: Um, actually, I'm an experiment in genetic engineering. My DNA is half sugar, which is why I'm so cute.
That is because Scootaloo is the greatest pegasus ever, who will one day handily surpass Rainbow Dash. Losing her mom to a suave griffon, getting her cutie mark late, having a skater boi father who's kind of a ditz, it's all the fires that will form her in the crucible. Destiny has a plan for her, though I know not what!
Non destined Pegasi, however, are a different issue.