I try to translate all,, but i don't know it's correct ^^"
Yamachan : Merry Christmas. Let's have fun on this christmas. Let's to make it warm. Happy New Year! (Sorry i can't see what is kanji in this phrase) Let's fun with Hey! Say! JUMP in 2011.
Chinen : Merry Christmas. I'm your Santa. Happy New Year. I'm your rabbit. on the right is "I Love You"
Yuto : Minna~ Merry X'mas & Happy New Year. This X'mas let's spend your time with us and then New Year's Eve too. Let's spend our time. Let's have fun.
Ryutarou : Merry X'mas. Have a funny X'mas in this year. Happy New Year. This year a good year with you. This year is 4649 too. ( i don't know what is 4649 = =" )
I'm so sorry I'm not good at English T^T.
Credit pic :: taiyou_fon.@hsj-thailand.com // jesameresu