What I find funny is that while they would pick material from WEG's Scavenger Hunt to favour the gross exaggeration of the Bade Delta Zero order, they literally omitted to look in this Death Star guide.
The guide in question said that the habitable zone of the Death Star was actually located in the 2-4 km thick crust of the battle station.
It only had 7200 TIEs and two full legions of stormtroopers, along other DS troopers. The total didn't even cross half a million, with people often gathering in smallish and numerous city sprawls on the surface.
The WEG actually gave the battle station a crew number of 265,675, including 57,276 gunners.
607,360 troops, 25,984 stormtroopers (largely acting in a milice way to keep an eye on everything and impersonate the Emperor's fist), 42,782 starship support staff, 167,216 support ships pilots and crew.
Now, the pop number was revisited in the novel Death Star, but with little change to some statistics, less than we may think:
Death Star, p.8 wrote: True, as worlds went, what was taking form three hundred kilometers from his flagship would not be quite as imposing as Imperial Center, say, or Alderaan. But when finished, it would be larger than two of the satellites of his own planet Eriadu, and it would be home to well over a million beings.
The "troops" being both DS troopers and stormtroopers (including specialized squads).Death Star, p.10 wrote: Aside from the fearsome, world-destroying "superlaser" itself-which was based upon the Hammertong Project and used a power source secretly taken by the 501st Stormtrooper Legion on Mygeeto during the Clone Wars-the station would mount a complement of craft, both space and ground, equal to a large planetside base: four capital ships, a hundred TIE/In starfighters, plus assault shuttles, blastboats, drop ships, support craft, and land vehicles, all ultimately totaling in the tens of thousands. It would have an operational crew numbering more than a quarter million, including nearly sixty thousand gunners alone. The vessel could easily transport more than half a million fully outfitted troops, and the support staff-pilots, crew, and other workers-would be half that number. The logistics of it all were staggering. Oh, it would be a fearsome monster indeed. But a monster tamed and under Tarkin's control; a monster sheathed in quadanium steel plating, invulnerable and impervious.
As we can see, the population number is actually a direct port from WEG's figures.
WEG's guide says that most of the DS' structure was devoted to machinery.
More than likely largely automatized and maintained by legions of droids.
On another note, both WEG and the ICS, although disagreeing on the real shape of the power core, agreed that it was massive and took a lot of room, both upwards and sideways.
Which makes wonder if, in light of the size of the DSII's core, if the DSII was really more powerful.
On another note, it also explains, via a note from Tarkin to Palpatine, that Oversectors should be primarily created to encompass several problematic sectors.
Others details were open to retcon.