I thought the pink was because of her Quirk?I get the feeling that Mina gets more focus in general conversations than Momo, Jiro or Tsuyu (or Toru of course), just because her extroverted personality makes it easy to write in her comments on whatever is going on at the time. But of course that's very different from being involved in the action or delving deeper into the character.
I wonder if one parent provided the pink, and the other provided the horns. Hmm...