K2 Classmates

We intend to hold a belated birthday celebration for Oliver in school on 13 Dec. But we somehow could not remember all the names of Oliver's class mates, including Oliver.
Boys (7)
Caleb
Christopher
Edison
Jun Kiat
Oliver
Yu Yuan
Who is the missing boy? Finally found out who and surprisingly he was not around during Oliver's birthday celebration.

Girls (7)
Boon Shuan
Clarissa
Shanice
Shania
Tarryn
Yun Xuan
Yijing