Whisper Tunes

I saw the question but never read all the answers so if someone already explained it then i'm sorry for repeating it. The depiction of Celestia in Twilights book "the tale of the two sisters" in the first episode has a pink mane and tail. But nightmare moon also had red eyes. I'm guessing the original plan was to give her a pink mane and tail but it was dropped in favor for less "girly" colors. And maybe the regie noticed that red eyes might be to scary looking for little kids. Or something. That's my theory.