Based on the official group shot posters:
Season 1 (http://www.sporcle.com/games/BartonFink/my-little-pony-friendship-is-magic-characters-pic)
Season 2 (http://www.sporcle.com/games/BartonFink/my-little-pony-friendship-is-magic-s2-characters-pic)
I had to LOL when I saw the MMMystery "antagonists" in their Pinkie dream sequence costumes, Granny Smith with her army helmet and Vinyl and 'Tavi's antics on the Season 2 pic.