Awww! This is cute. Though it isn't quite Christmas yet where I am, it is Christmas in Korea so MERRY CHRISTMAS! Jung's poster is aimed towards the singles and roughly means to give them some fighting spirit.
Yoo Sun's poster says, "With passion, anyone can have a merry Christmas!"
Then here come the high school students looking adorable!
From left to right:
"Even cold (impersonal), city men have a warm Christmas!"
"Nuna (term for older women used by males), Merry Christmas. Accept my 'eye-smile' as a present"
"During Christmas, gather up the courage and propose to the one you love!"