Oh, what a shame. I have an awesome Firefly cosplay group going, but the costume I worked hardest on is for Once Upon a Time, and they're having their meetup at the same time.
Angelica Teach (Pirates of the Caribbean: On Stranger Tides
D'Anna Biers/Number 3 (Battlestar Galactica)
Emma Swan (Once Upon a Time S1)
Captain America (Retro Lady Avengers Group)
Steampunk Carmen Sandiego