A double engine failure by the time of impact seems to be inferred from the state of the physical wreckage and the battery drain warning. However, that warning is reported to have followed a low-rpm warning, so was an engine still running at the time of the rpm warning (seems unlikely?).
From the lack of timestamp information in the FADEC memory, it doesn't seem to be clear what the interval was between the two engines stopping ("a short time"), although the AAIB seem confident that the right engine stopped first, presumably based on some unstated concrete information, rather than just by being consistent with the relative supply tank sizes.
The difference between the engines' run times is known, but will it ever be known which was started first, and the gap between the start times? Whether there was time to land with one engine still running after the first one failed seems to be unclear.
The eyewitness reports of low flying before the crash seem to be incorrect, given that the report says the steady radar returns before the accident were from 1000 feet and 105kt.
This report seems to rule out some dramatic mechanical issue, so the focus now falls on the mysteries of human factors, and, as stated by "Art of flight", whether the failed display system might have prevented the recorded warnings, and perhaps the state of the pumps?, from being appreciated onboard.