There's an error I don't know how to fix
Putting all other possible issues aside such as pin and timing conflicts. 

Rename the sketch setup() and loop() functions, for instance, rgb_led_setup() and rgb_led_loop(), and peizo_setup() and peizo_loop(), then rewrite:

void setup() { 
  rgb_led_setup(); 
  peizo_setup(); 
} 

void loop() { 
  rgb_led_loop(); 
  peizo_loop(); 
}


Cheers!