[matsunaga_hisahide]

Naruto Ultimate Ninja Storm 2 Roster Screenshot

There 42 roster spots.

Seeing as Minato and Tobi are confirmed in this scan -
Minato and Tobi revealed scan

as well as the leaked Trophy list -
Trophy list leak link

Spoiler for Full Trophy List:

* Prologue Complete
You have completed the prologue
* Chapter 1 Complete
You have completed chapter 1
* Chapter 2 complete
You have completed chapter 2
* Chapter 3 complete
You have completed chapter 3
* Chapter 4 complete
You have completed chapter 4
* Chapter 5 complete
You have completed chapter 5
* Chapter 6 complete
You have completed chapter 6
* Final chapter complete
You have completed the final chapter
* Naruto’s Friends
Now you can use age companions from Naruto’s generation
* Narutos Teachers
Now you can use Kakashi, Yamato, Gai and Asuma
* Friends from the Hidden Sand Village
Now you can use Gaara, Kankuro, Temari and Chiyo
* The legendary Sannin
Now you can use Jiraya, Tsunade and Orochimaru
* Mysterious Akatsuki
Now you can use all members of Akatsuki
* Hebi is on the Way
Now you can use Sasuke, Suigetsu, Karin and Jugo
* Assassine from Tekken 6
Now you can use Lars
* Bell Stealing Expert
You have received the S-Rank in ‘Bell stealing Lesson’
* Village guard
You have received the S-Rank in ‘Sand- and Art-Explosion’
* Being spared by the Puppets-Jutsu
You have received the S-Rank in ‘Sakura’s Dance’
* Unstoppable Rampage
You have received the S-Rank in ‘Forbidden Rage’
* Difference in the growing up
You have received the S-Rank in ‘Final Battle among Friends’
* Return of the fourth Ho-Kage
You have received the S-Rank in ‘Sturm und Drang’
* Foaming over Hatred
You have received the S-Rank in ‘The both Uchiha’
* Overpowering Sage
You have received the S-Rank in ‘Battle of the Sagegod’
* Vision of a new wind
You have received the S-Rank in ‘Convulsion’
* Cursed Dolls eliminated!
You have retrieved all cursed Dolls
* Quiek!
You have retrieved all of Tonton’s pearls
* Exam passed!
You have passed 10 exams
* Exam Master
You have passed all exams
* Post-Ninja
You have complete all correspondence events
* All Friends are here!
You have seen friendship events for everyone
* Nothing gets past you
You have collected 500 Items
* Money makes the world go round
You have saved 999999 Ryo
* Points-Tycoon
You have collected 999999 Stormpoints
* I Love Ninja-Tools!
You have received all Battle-Items
* Roaring trade in the general store!
Du hast alle Sammel-Items gesammelt
* First editing
Edited a Ninja-Info-Card
* News-Ninja shocks!
You have collected all carrier pigeons
* Flashback complete!
You have collected all memories
* Story-Collector
Found 100% of the Story
* Thanks for all your time!
Your overall playtime is over 30 hours
* On the way to the Ninja!
You have won 10 times in online matches
* Expert Ninja
You have won 50 times in online matches


Silver Trophies:

* Fragment complete
You have completed the Fragment
* Assembel all Ninjas!
Now you can use all Ninjas
* The unflashy Detail
You have seen all secret factors
* Also known as…
You have received 50 Titles


Gold Trophies:

* All events complete
You have complete all events
* Card Collector
You have collected all Ninja-Info-Cards
* How should I be called?
You have collected all Titles


Platinum Trophies:

* A perfect Storm Master
You have received all 50 trophies

It means that:
- Story consists of Prologue, 6 chapters and the final chapter.
- Boss battles (probably):
* Bell Stealing Expert
Naruto/Sakura vs. Kakashi
* Village guard
Gaara vs. Deidara
* Being spared by the Puppets-Jutsu
Sakura/Chiyo vs. Sasori/100 puppets
* Unstoppable Rampage
Kyuubi vs. Orochimaru?
* Difference in the growing up
Naruto vs. Sasuke? Maybe something with Kakuzu and Hidan?
* Return of the fourth Ho-Kage
Don´t know...maybe Minato vs. Tobi/Madara? Naruto vs. Kakuzu?
* Foaming over Hatred
Sasuke vs. Itachi
* Overpowering Sage
Jiraiya vs. Pain(s)
* Vision of a new wind
Naruto (Sage or Kyuubi) vs. Pain/MS Sasuke vs. Killer-Bee?
- Seems that you can collect some items like Cursed Dolls, Ton-Ton's pearls and carrier Pigeons
- Also there are "letter deliver"-missions and Friendship events you encounter in the areas.
- Then is the returin of Ryos to buy items and Stormpoints, probably to by new justsu scrolls.
- Also seems the memories return (if they are those little sweet picture-book styled animations)

Also thanks to scans and the trophy list, the final roster pretty much looks like this:

Naruto, Sakura, Sai, Shikamaru, Ino, Chouji, Neiji, Lee, Ten-Ten, Kiba, Shino, Hinata, Kakashi, Asuma, Yamato, Gai, Jiraya, Tsunade, Orochimaru, Kabuto, Gaara, Kankuro, Temari, Chiyo, Sasuke, Suigetsu, Karin, Jugo, Sasori, Deidara, Kakuzu, Hidan, Itachi, Kisame, Konana, Pain, Tobi, Killer-Bee, Fourth Hokage, Lars, Kyuubi/Sage Naruto (depends on which transformation the normal Naruto has), Cursed Seal/MS Sasuke (depends on which transformation the normal Sasuke has)