First, let's identify the tunes:
Jingle Bells
Have Yourself A Merry Little Christmas
Here Comes Santa Claus
Rudolf The Red-Nosed Reindeer
Frosty The Snowman
Feliz Navidad
Happy Xmas (War Is Over)
Now, there's something not quite right about those scores:
There's no time signature on any of them, and the bars aren't consistent lengths.
In fact, it looks like there is one bar per word of the song title, with one note per letter in each bar.
Extracting the corresponding letter for each note and sorting by colour gives us:
Light blue: JOLENUOYXE
Yellow: NEEFRIHHCTEONWHA
Dark Blue: ELVECESOENAV
Green: BATOULNENA
Pink: SARTMCHRERMYSI
Purple: FELIZNAVIDAD
Finally:
Those are all anagrams of Merry Christmas in different languages:
Light blue: Joyeux Noel (French)
Yellow: Frohe Weihnachten (German)
Dark Blue: Vesele Vanoce (Czech)
Green: Buon Natale (Italian)
Pink: Merry Christmas (English)
Purple: Feliz Navidad (Spanish)