Love Letters (Straight from Your Heart). The definitive version of this is by Ketty Wells. Lynch used it in Blue Velvet to devastating effect. I didn't try to copy the haunting piano part, instead taking a different approach entirely on the electric guitar.
Bad Boy. The only version I know is by Bombers. The singer is phenomenal, despite this crazy vocal technique billed as the "human echo box" that he used on every song. (I chose not to copy it.) The chuckling is my own contribution.
Endless Sleep. This is an incredible piece of songwriting. The image is so haunting, so vivid. I felt that the denoument in the original was a bit of a cop-out, though. It would have been better if the sea had taken his girl. So in my version, I repeat the haunting phrase "endless sleep" at the end a few times, along with a creepy fade out and some ghostly guitar squeaks.
Update, Tuesday Feb 9: I redid the vocals on Bad Boy. This page now links to the new version.