
Quick answer — Momoko Ohara voices Ninomiya in Minami-ke, Shuuichi in Minami-ke, Yuu in Minami-ke and 3 more characters.
Momoko Ohara voices Ninomiya (Minami-ke), Shuuichi (Minami-ke), Yuu (Minami-ke), Miyashita (Mitsudomoe), Osamu Momochi (Level E), Nao-chan (Kanamemo).
Ninomiya is voiced in Japanese by Momoko Ohara.