for those that played the japanese version which scenario has the most spoilers and which one has the least spoilers? thanks.

They all have approximately the same amount of spoilers.

The story is pretty much the same. But you see it in three different ways. It doesn't really matter (As DChiuch mentioned) what story you choose.

Yeah, DChiuch pretty much answered it.

They all reveal stuff.

personally i think terras does by what i can see, not what i understand cause i cant read japanese. then id pick aquas, then vens.

Well I haven't played the game but I think that every scenario reveals different things but as Nomura recommended you should try to play the game first with Terra, then Ventus and last Aqua in order to understand better the history. Every scenario should have the same quantity of spoilers but to know better the story play as T-V-A

I believe its Ven's because

both Aqua and Terra's story has to do with Terranort

Yeah, essentially all three scenarios have the same amount of spoilers, but personally I find Terra's to spoil the most.