I had a bit of trouble trying to find a song for Pinkie's lead. But then I found one. I did have another one in mind, but after struggling with Pinkie's vocals, I chose another one which was easier. Singing as Pinkie is hard let me tell you. hehe

Applejack - Alto 2 (Lowest part)
*Bass Line
Twilight Sparkle - Alto 1 (Second Lowest Part)
*Percussion
Rainbow Dash - Soprano 2 B (Third Lowest Part)
*Guitar
Pinkie Pie - Soprano 2 A (Third Highest Part)
*Lead Vocals
Rarity - Soprano 1 B (Second Highest Part)
*Harmony 1
And Fluttershy - Soprano 1 A (Highest Part)
*Harmony 2