Yume Chu

From FCTranslations:
Azuki, a young girl whose father is the president of an entertainment corporation, is always out of luck when it comes to dating. It seems like every boy she had dated before all tried to use her as a bridge to get into the world of media. So when Azuki met the guy of her dreams, who also happened to be a contestant in the audition her father set up, she wasn't so sure what to do anymore.

*Contains in the 4th volume, Juliet Club:

An idol in a famous group tries to escape from his fans by studying in the library. There, he meets a girl who he mistakes as one of his fans and tries to send her away. It turns out that the girl actually doesn't know that he is an idol. They continue to study together in the library, neither of them knowing the other's name, while love slowly blooms between them...

*Also another story titled We, the Demon, and Christmas

Every year at the time of Christmas, the demon appears, and the Angel twins intend to catch him.