From the interim report
1.1.3 On 06 July 2018 maintenance checks (A, B & C) were performed on the aircraft at 18115.1 airframe hours The accident flight was the first flight post maintenance.
Since the first flight after maintenance is basically a test flight I'm surprised they'd be taking passengers. Since it's unknown what issues will occur it makes more sense to have the minimum number of people on board and to keep the weight as low as possible.
I wonder if the outcome would have been different if they'd done this.