Here are some lyrics I know for scenes:
Sesame cast intro
Kermit: It's the Sesame Street gang!
(everyone cheers)
Big Bird: Merry Christmas, everyone!
Other SS cast: MERRY CHRISTMAS!
(sung)
Big Bird: Deck the Halls with boughs of holly,
Other SS cast: Falalalala,lalalala!
Cookie Monster: Tis' the season to be jolly,
Other SS cast: Falalalala,lalalala!
Grover: Don we now our gay apparel,
Other SS cast: Falalalala,lalalala!
Natalie/Gladys: Join the ancient yuletide carol!
Other SS cast: Falalalala,lalalala!
Big Bird: Your turn, Ernie and Bert!
Ernie: See the blazing yule before us,
Other SS cast: Falalalala,lalalala!
Bert: Strike the harp and join the chorus!
Other SS cast: Falalalala,lalalala!
Oscar the Grouch: I will NOT sing this song!
Other SS cast: Falalalala,lalalala!
Count Von Count: While I count the yuletide treasure!
Other SS cast: Falalalala,lalalala!
Big Bird: Your turn, Herry Monster!
Herry: Fast away the old year passes,
Other SS cast: Falalalala,lalalala!
Guy Smiley: Hail the new year, lads and lasses!
Other SS cast: Falalalala,lalalala!
Two Headed Monster(?): Sing we joyous, all together.
Other SS cast: Falalalala,lalalala! Deck the halls with bounds of holly, tis' the season to be jolly, Falalalala, falalalala, falalalala,lalaaaaaaalaaaaaaaalaaaaaaaaaaaaaaaaaaaaaaaaaaaa!
(Song ends)
(Film leader countdown (4) (3) 2, then piano intro)
Baby Piggy: You'd better watch out, you'd better not cry...
Floyd Pepper: It's Miss "Ham-heart" when she was just a little sausage roll!
Babies: ...is coming to town!
Baby Fozzie: AaaaaAAAAAAaaah! He's making a list, and checking it twice...
Mrs. Bear: You were still in diapers in those days!
Fozzie: MOOOOOm!
Babies: ...Claus is coming to town!
Baby Rowlf: He sees...
Offscreen Muppet: Hey, there's Rowlf when he was a real puppy!
Rowlf: Not so wee! I was paper-trained!
Baby Gonzo: He knows if you've been bad or good, so be good for goodness sake! Oh,
Gonzo: I was a little devil back then!
Babies: You'd better not pout, I'm telling you why.
Baby Piggy: Why?
Babies: Santa Claus is coming to townnnn!
(Baby Animal breaks out of a present.)
Kermit: Oh, Animal!
(Footsteps are heard, and then adult Animal rips a hole through the movie screen.)
Everyone except Animal: OH ANIMAL!
(Everyone cheers.)
Scooter: (shutting off projector) Yep, some things never change!
And remember when Doc dressed up as Santa Claus?
"Santa": (loud jolly Santa voice) Ho-ho-ho! Merry Christmas!
Everyone except "Santa": IT'S SANTA! (cheers)
"Santa": (Doc's voice) Merry Christmas, everyone!