I'm not sure what you're after Ragnar, the pz3 saves everything in your scene including the lights, how many, what settings etc. everything. I really don't know what else you need! The pz3 has it all as you have said above!

From my understanding the python script "collectsceneinventory" does just that, tells you exactly what you have in the scene just in case there is a prop or something hidden away that you can't actually see [I could be wrong]!

Injustice will be avenged.
Cofiwch Dryweryn.