Bon Bon is a cocky Canterlot mare. Lyra is a happy go lucky pony. Together, they will save Equestria. Well, other ponies might.... These two are mostly just happy to pay the rent.
"Hmm... well..." Rarity said, starting to blush. "Rather than a prince, what I would say is best suited for a fair maiden such as I is, a knight. Perhaps rougher around the edges, but charming in their own way regardless. Bold, courageous and unwaveringly loyal–the resilient sort who would push past the limits of what even seems feasible just to save somepony in need."
So, Rainbow Dash.