could somebody please tell me their real name according to order, ruki, reita, uruha, aoi, kai. thanks.

Ruki - Matsumoto Takanori
Reita - Suzuki Akira
Uruha - Takashima Kouyou
Aoi - Shiroyama Yuu
Kai - Uke Yutaka অথবা Tanabe Yutaka, depending on your sources.
Naturally, their real names are surname first, forename second.