Hyorin from Sistar ^^

2nd idol:
He is a maknae of a group. He is close with EXO's Kai , he is born in 1993. His group has 5 people in it beginning with S. He is on WGM a korean show , with a member of Apink.
Clues- He is a maknae , Group has 5 people and on WGM.

Taemin from Shinee

3rd idol:
She was voted best looking female idol on "Weekly Idol". She has a big brother born in 1992 and she is born in 1993. Her name begins with J. She is friends with Luna and IU , she is in a group starting with the letter T.
Clues- Born in 1993 , friends with Luna and IU , voted as best looking female idol on Weekly Idol.

Jiyeon from T-ara

4th idol:
She is born in December , 1989. She is in possibly the best group in the k-pop industry. They debuted in 2007 , in her group their are 9 members her name begins with Y and group begins with a S. They won the Mama Awards (obviously one! :P)
Clues- Group won Mama Awards , Born in 1989 and has 9 members in the group.

Yuri~~!! SNSD ^^

Yup! Yuri!<3

5th idol:
She is born in August , 1993 along with another member of her group. Her group begins with A , a member left and is getting replaced some time. Her name begins with E and has around 50% of the groups popularity. She is main vocalist and one of their newest song is "U You" which has been nominated in the Eat Your Kimchi Awards 2013 for best Aegyo!
Clues- Born in 1993 , name begins with E and group begins with A.

Eunji ^^ A-Pink

Yup!