Design review - RGB LED color mixer using PWM
What is your LED part number? Please provide a link.
Is it REALLY 2A rated? 

As shown your pots are in PARALLEL with your fixed resistors so will REDUCE the resistance to below 3 Ohms.   

500 Ohm pots are too large - you will have to set the wiper very near one end and have minimal control. 

Each LED colour has a different voltage drop UNLESS they already have internal resistors.   Red LEDs about 2V.
Green and blue closer to 3V.

The AA supply using Alkalines will be 4.9V when new, will rapidly fall to about 4V and then over time fall to about 3.3V.
At 9.6 ohms and even 0.5A you will drop V=IR = 0.2 x 9.6 = 1.92V.
At even 0.5A if you drop 1.9V you will have too little voltage except when the battery is very new.

Giving more detail will help us help you.
Especially LED specs.