No$GBA doesn't have save states for DS game yet, and also, it's almost impossible to hack a save for a DS game so far.
Some more information:
Unlike the PSX version, where you have to beat the game multiple times to get all the extras, are unlocked when you get the tech, monster, item, hear the music, see the movie. Some picture are unlocked, when you get the characters, or when you complete certain events.
I'm not sure what the other 2 options are yet, but one has to be for the treasure chest thing.
You can unlock the extra mode music, by going into the arena and starting a match.
Also, another good reason the japanese version only allows 5 letters is because of the japanese text, if you have over 6 letter names, it would break the text.
The us verison should have English, French, Spanish on it, and maybe German, no word on if the Japanese text will be in it or not.
Also, the extra final boss has been leaked.
sorry no spoilers.