As Scott suggested, you really need to expand upon this some. You don't even really say in the plot where the RP takes place- in the Naruto world, or the Pokemon World, though your sign-up does suggest that it would be in the Pokemon World. Unless you plan on changing a lot of how the Pokemon World in general works, and make it more ninja-based instead of trainer-based, I'd say that the Naruto World with Pokemon would be a better choice of location.
Also, your plot has very little description at all outside the fact that there are these strange scrolls. Where did they come from? Why do these jutsu's give you the power of the legends? As a suggestion, maybe you could do something along the lines that the souls and powers of the Legendary trios were tied into these scrolls long ago, and by mastering the jutsu, the legendary becomes a part of you, and through using the jutsu itself, you can use that Legend's powers. Of course, you can do whatever you want, that was just a suggestion.
You don't really explain how the characters obtained these scrolls, either. Maybe they found them, or it was handed down through generations. Or, maybe it was given to them by a strange person, something like that. Of course, you'll have to have a reason why if you chose the latter.
You also don't have a conflict. With something so powerful, you'd think there'd be something out to get them, wouldn't you? A roleplay is boring without conflict, so adding something here would make things much more interesting.
One last thing. Your sign-up sheet leaves a bit to be desired. Usually, when creating one, you want to put the shorter answers, like name, age, ect., up at the top, with longer sections like description and personality more towards the bottom. If I could suggest a sign-up form for this RP, I'd say you should go with something like this.
Pokemon in Scroll:
Something like this would be ideal, but feel free to mix it up to however you want it, just making sure to begin with Name, Age, and Gender. Also, you really need both Description and History in a sign-up, so that you can describe your character and also what happened in his or her life to make them who they are today. History can help make a character, and often people model their characters after their History.
Overall, I really do think this RP has a lot of potential. It just needs to be added to and made all it can possibly be for it to succeed. I have no doubt that it'll do well once you get it going and change some things, though. There's lots of RPer's here who love Naruto. Just put a bit of effort into the storyline and you'll have an awesome RP. ^^