The roster for the X-Factor team is Jamie Madrox, Layla Miller, Rictor, Shatterstar, Siryn (sadly only for Heroescon), and hopefully a Strong Guy for NYCC. It all depends on who's going to what con, etc.
That sounds so cool! Please post pictures of your group! I love X-Factor so much and I'd love to see more people cosplay Siryn especially.