merry Christmas (war is over) by John Lennon
"In Dulci Jublio" - which means "Good Christians Rejoice"
All I want for Christmas is you - Mariah Carey
Go Tell It on the Mountain
Long Time Ago In Bethlehem, So The Holy Bible Says. It is the first line of Mary's Boy Child.
Lpiacs Christmas song = Lonley Pup In A Christmas Shop, by Adam Faith.
If one of those letters is wrong, it could be "Here we come a wassailing among the leaves so green". That's my guess!
It's the Most Wonderful Time [of the year]...
The Angel Gabriel from Heaven Came
That was a hard one, I found it under Rare and Unusual Carols. It is "Thou Who Wast Rich Beyond All Splendor", Written by Frank Houghton in 1934.
The initials HTGS would fit the Christmas song "Hark the Glad Sound", written by Philip Doddridge (1702 - 1751).
The Chrismas song that has the initials JTTW is Joy to the World.
I think it's Wise Men Seeking Jesus?
chestnuts roasting on an open fire