Wow, I always thought it was Donald Novis! The vocal sounds a lot like the voice of "Love Is A Song" and the Golden Horseshoe track on the DL boxed set, so I never doubted the credit. Learn something new everyday.
In any case, it's a beautiful song, and I love the mood it sets to start this film...
Speaking of which, I was messing around with my Lady and the Tramp DVD the other day, experimenting with whether the 5.1 ("Enhanced Home Theatre") or 3.0 (Original Theatrical) mix sounded better while using my headphones, when I noticed something about this track I had never noticed before although I've watched the film and listened to the soundtrack many times...
I'm sure most if not all of you know this already, but the backup choral sound in "Peace On Earth" is actually to the exact melody of Silent Night. I felt kind of silly for just noticing this now - I attribute it to the fact that when I listen to music I tend to follow along with the main melody (especially lead vocals) and usually don't "isolate" any other sounds in the mix other than how they sound against the main vocal/melody line.
But comparing the 2 mixes on some of the songs, I was actually listening for how clear/audible the various elements in the mixes sounded in each mix, and that's how I finally noticed this!