Danny Boy
Rock n' Roll Doggie FOB
Is the track available to buy yet?
Not yet that I know of.
This reminds me of when Pearl Jam covered "Love, Reign o'er Me" for the movie Reign Over Me a couple of years ago. It was a fairly popular track but it didn't appear on the soundtrack CD.
They eventually released it as a single on iTunes, so hopefully the same thing will happen with Winter.
However, "Don't Come Knocking" never got released.