Having spent many hours in the belly of the beast during the 747-8F flight test program, there are multiple issues - not all easily addressed.
Pax O2 is easy - as noted above seat mounted O2 bottles.
Evacuation is a bigger problem - there is only one main deck door on a 747F that can be readily opened from the inside during an emergency (regulations require at least two exit paths since you assume half are unusable in an evacuation). For the 747-8F flight test, they'd installed a special system that allowed us to open the main deck side cargo door from the inside, with ropes for escape. No idea what they did for the Kalitta flight in question but best guess is they got some sort of one flight exemption...
Then there is passenger 'comfort'. There is only one lav on a 747F, and it's on the upper deck. Even with only ~30 people on a flight test, on a longer flights lines to use the lav were common. The linked article says the upper deck was closed off (to prevent the flight crew from exposure) so no even that was available. I suspect some sort of 'porta-potty' was installed on the main deck.