I still haven't watched the new episode yet, which is odd, since I love Spike. He was actually my first favorite character.
In the meanwhile, I'll catch up with some topics.
Who are your favorite(other than the main 6): Unicorn; Pegasus; Earth Pony?
Unicorn: Shining Armor
Pegasus: Scoots, Soarin, Star Hunter, Prism Strider, Great Scott
Earth: Orion, Rose, Sweetie Drops
I don't have an OC pony. I've put all of my pony creativity into Orion.
My favorite song would probably have to be the Cutie Mark Crusaders theme song. It's the only song I have saved to my favorites, though At The Gala is a close second.
I don't really remember any of the songs from season 2, and I haven't given the season 3 songs a lot of listens, so I don't know them that well.