... not to be argumentative, but which covers has he done his own arrangements for?
Always Be My Baby, Baba O'Riley, and (my personal favorite) Little Sparrow. I think Hello was somewhat inspired by the Incubus version, but nowhere near a carbon copy.
I think he'll do great, so long as he sings his ass off. And he usually does, so I'm really looking forward to tonight. Of all the Idol contestants I've ever heard, he's the one I'd most like to hear sing U2. Should be good.
(Think they'll bust out the choir and have him do the Rattle & Hum version?)