The Johnny Cash songs work for the achievement. I got it after playing I Walk The Line.
Did you try sorting by year in-game? I'm pretty sure I saw Ooby Dooby listed under 1950whatever, but I know I saw the Johnny Cash songs according.y
DLC on DLCQuickPlay.com. Gamertag is the same as my Forum name. Hit me up if you wanna play!
No, Ooby Dooby was confirmed not to work since before the game's release.
But some Johnny Cash (not Ring of Fire, but definitely I Walk The Line) get the achievement.
My tumblr page, yo: http://heyitsmario.tumblr.com/