What Characters Should I Use?

Even though it might be a while before I can actually start on the new mlp project I am probably gonna need to either make or remake a bunch of the actors either way and I don't know what characters to really use! Here's some of the "plot": Poker is involved and from what I read, you need at least six players for the best game possible. Now, I know Derpy and Rainbow Dash are 100% certain, Applejack is a maybe because of Texans and card games. But other than that..I don't know!