How exactly does the new 100+ button Rock Band 3 guitar work in-game?

I know there is a new guitar being released that has buttons laid out to simulate frets by putting them in 6 rows of however many buttons. I have a few questions about how that guitar actually works in the game.

• If I were to buy this guitar, could I also use it to play the non-pro versions of guitar tracks? That is, the tracks that have 5 colored buttons.
• Can I use this guitar to play bass parts?

Yes, you can play both standard mode and the bass parts with the Mustang.

Frets 1-5 are used to simulate the Green->Orange buttons that you may be used to on the standard RB Strat, though they're wider. You can also use frets 13-17, which are narrower and liken a bit more to the solo buttons from the RB Strat, and they function in the same manner in which you don't have to strum for the solo/Big Rock Endings parts. You can press any or all buttons on the appropriate fret, it doesn't matter which 'string' the buttons are on, and similarly you can strum any string whether you're fretting it or not.

For the bass parts in Pro Mode, you can simply ignore the 2 strings you don't use (B and high E).

According to this, you can play non-pro and bass.