Im using a single 12F683 (or 12F675) for controlling the RGB channels and I still have space for an extra potentiometer (for sweep speed) and 2 buttons.



For PWMing I use PWM instead HPWM, of course if you have 3 HPWM is a little easier, but not much...

you share a common ground and use a 7805 regulator for the pic, then you can power the regulator and the leds with any value from 5-24V (+ after the resistors)

I drive luxeon leds without problem

Have fun