What's funny is the Little Ladies event also had a similar voting event. From what I remember the winning Songbird did vary for each server/datacenter. The outfit (from another year) is just a default white like said above.

Really, people shouldn't be surprised that Astrid won. She the most biased pick for having the theme colors and for being the most familiar character out of the three. And this sounds shallow, but If the other two looked more appealing color-wise and appearance-wise, then maybe the outcome would've been different.