Of the 25 characters; these are confirmed:
Naruto Uzumaki
Sasuke Uchiha
Sakura Haruno
Kakashi Hatake
Rock Lee
Neji Hyuuga
TenTen
Gai Maito
Shikamaru Nara
Chouji Akimichi
Ino Yamanaka
Kiba Inuzuka
Shino Aburame
Hinata Hyuuga
Jiraiya
Orochimaru
Gaara
Temari
Kankurou
Kisame Hoshigaki
Since Kisame is in, it's fair to say Itachi will be aswell. And i'd like to see Kimimaro, Haku and Zabuza in it aswell, and probably Tsunade and Kabuto. So probably no sound 4
