The entire Mane 6 need to be in the next SSB as one character.

You'll be able to change between each pony through the color swap at the character select screen.

Final Smash? Elements of Harmony (Duh.)

All 6 will come together in the center of the stage, and a pulse will grow from the center knocking all players off the stage. (Similar to how the Changelings were repelled from Canterlot Castle.)

YES!