Resistors not needed. Outputs are actively driven High and Low.
The only time of concern is during reset when all pins are inputs. If you want a specific level, then use a 5K to 10K pullup to keep the PNP off if desired. Or a pulldown if you want it on.
Analog pins can be treated just like digital pins with
digitalWrite(pinX, HIGH); //or LOW
with
byte pinX = A0;
altho I prefer using the digital pin number - A0 = 21 on a Mega. Or 22? Not sure, never actually used a Mega, and haven't looked at pins_arduino.h in a while.