I’m also planning on controlling each pixel. I thought of ways to do it as well. 256 buttons seems like too much. I decided on a controller where I have joystick and 2 buttons. One button will turn on a selector. This will blink a white light on the pixel that is selected. The other button will paint the color/cycle through colors. The joystick navigate over all the pixels. When I’m done painting, I click the select button again to stop it from flashing.
Also, since I have a controller, I might try to program games like tetris and snake.