The resistance can be set as desired according to the required brightness of the LED.
Furthermore, the one LED that lights up when digitalWrite is set to LOW always consumes current.
It only goes off when digitalWrite is set to HIGH, but the current is only changed to flow through the MOSFET instead of the LED.
In addition, the other lit LED draws current from the port, which increases consumption.
In other words, it is best to set the less frequently used LED (red in your case) to the side that lights up when digialWrite is HIGH.
After that, you can freely change the resistance value according to the brightness.
By the way, it is possible to provide the four states of
both OFF ,
red ON / green OFF ,
green ON / red OFF and
both ON(orange light?)
with a common cathode LED at single Arduino output pin.
But the Arduino output pin must be a PWM capable pin, and use one hardware timer...