Yes, 800 tonnes, would roughly translate (saying that the avarage human being in the future is 80 KG, which is a bit unrealistic , since women are on avarage 50 and men are 70), to about 10,000 raw passanger weight, obviously lugage, personal possessions, and the compartments themselves would shave of a significant chunk of that, but still no matter which way you calculate, with comparison to numbers that we already have on our ships, Beluga in particular and her arragement makes no sense whatsover.
For people who are saying oh these magical modules or whatever that do this and that, technicly by that logic they are so big on beluga that the passanger space would be something like Tokyo motels, judging by this logic