you're right, high density seating is an understatement.
398 people in economy is too tight, and 8 crew.
Usually on this aircraft the IFE and lights go out in "E" zone, or the lights come on in the middle of the night, then 398 people want to go walk around.
They should sell the thing or simply convert it to cargo... do anything but dont put people in it.
Not long ago we had to place the cardboard on the floor to soak up the liquids that were coming from the drain, the punters loved having their feet squishing around!