"Have Yourself a Merry Little Christmas"
I heard this on the radio (which reminded me that I hadn't listened to the album yet this year), and I noticed three things that I wanted to write about, but after looking into them, only one turned out to be viable: the "star" in "Hang your shining star above the highest bough" is just a half-step above the "bough," so pitch-wise, the "star" is "above the highest bough." The "star" is sung to an A, and the "bough" to a G#.
"I'll Be Home for Christmas"
The Carpenters' version starts with a couplet that I haven't heard in any other version. It's:I’m dreaming tonight of a place I love even more than I usually doand then it goes into "I'll be home for Christmas / You can count on me...."
And although I know it's a long road back, I promise you
There's a grammatical ambiguity with "even more than I usually do," specifically what it's referring to. It could be either "I'm dreaming tonight of a place I love even more than I usually [dream about it]" or "I'm dreaming tonight of a place I love even more than I usually [love it]." Either parsing is valid, and it could be understood either way.