I've read a lot about this topic, since I'm something of a Coulton fan, and I'm something of a network non-fan.
It appears that absolutely nothing on Glee (music or dance moves) is original to the show.
They will do covers of famous songs with the exact same arrangement. Or they'll do less-famous covers of those songs that they can pass off as their own (no credit for the new arrangements anywhere official). And for the dance moves, one Hollywood choreographer has mentioned that he's been approached more than once to work with the show, but that instead of asking for new moves to go with the music, they want their choreographers to take dance moves created by someone else and use that step by step adjusted to fit their cast. He refuses and calls what they want the equivalent of taking a book that's in the public domain and copying it word for word and republishing it.
Coulton hasn't updated his blog regarding this, despite the fact that he figured he'd have an update the next week after his post about how he was going to protest this treatment by releasing the cover of the cover. And now he's on a boat, so he'll be incommunicado until the JoCo Crazy Cruise returns to port in a week.
That silence makes me suspect that there is actually some merit to the accusation that Glee used his actual audio tracks, which is a huge no-no with precedent being set that even using 4 seconds of someone else's recording is a violation and will land you in hot water. My suspicion is that the people at Glee figured that as long as they stomped all over indies and relative unknowns that they could keep doing this until the rating dropped enough to shut the show down.
As regard their using his arrangement, there's nothing illegal about that, as the license that granted him the ability to create and perform the cover gives all rights to that back to the original artist, making it part and parcel with that for anyone who comes along later to use in their own cover. That doesn't make it wrong, just not actionable.