What I think is that the noise system will be that you can change to whatever noise you want in each battle but you'll start a low noise level and as the battle progreses, you're Noise level will increase.
As for switching adapters, I think this will allow you to play as other characters, why else would teh yshow info about other characters Wave form on the RnR3 site.
So you probably lay as other characters or:
Whatever FM-ian you have with you, thats the Noise you'll turn into.
(I'm leaning towards this.^)
I'd enjoy that. :D --- Me is smart! You is Dumb! =D