You can not battle naga.He can only be seen.
You first go to the bakugan store (which is northwest of dan's house) talk to the shop keeper and choose the option: "get bakugan" you see which one u want and voila! u have bakugan!
Leonidas will evolve at the end of the game when you face Vladitor. The other brawlers' bakugan evolve shortly before that.
You have to enter a code when you name your character at the beginning. 449824934071 should unlock a bronze warius.
no you cant i think the bakugan game creators thought only boys like bakugan