I know that a high voltage coming to CNTRL_L0 will illuminate the LED attached to ANODE_LEVEL_0 but I'm not sure why all of this is necessary?
The 2N3904 is an NPN transistor, so when the CNTRL_0 is high the transistor is active and allows current through so that would mean the circuit connects from the first (on the left) +5V to the first GND and you effectively get a low going into the IRF9Z34N (the pMOSFET). That means the pMOSFET does not conduct, but so what? No matter what happens the ANODE_LEVEL_0 is connected to GND, wouldn't it always be illuminated? And if all that is needed to get this to work is that the 2nd +5V is cut off from the ANODE_LEVEL_0 then wouldn't a single PNP transistor joining CNTRL_L0, 5V and ANODE/GND do the same thing?