I have seen a gameplay video, and through that, I found the controls.
Note that the controls are translated from Spanish, and then rewritten by me to make more sense and I do not know if PS3 controls are the same as 360, because these are from 360, so some things may be incorrect. Also, note that these are only the controls that changed from IV.
LB/L1 - Weapon wheel
Press Left Stick/L3 - Stealth mode
Down on D-Pad - Change character
From what I can assume, the ability to flip off was just a lie by R*, but who knows?
I also don't have vehicle controls, sorry.