Re: crescendos on held notes
The way I've done it is to swap velocity and volume settings - it's the combination that creates the initial attack. Then, once the note is started and velocity no longer has any impact, you increase the volume setting (using an MPC) to match what would have been the velocity of the final sound had it been a struck note. Don't forget to reset the volume (AND velocity) for the next dynamic change.
E.G.
normal - Volume = 127, P(vel) = 45, F(vel) = 92
change to:
Velocity = 127, P(volume) = 45, F(volume) = 92