If a fuel exhausted aircraft impacted the water from altitude then you just wouldn't have 22 metre pieces of debris still floating. Three metres at a push but not twenty two.
When an aircraft impacts the earth or sea it is not uncommon for the tail to break off and remain intact, more or less, so a large piece floating, like the fin, could still be feasible.
Lawyers: Good luck to the ambulance chasers on this one, the pax are covered by the agreed passenger legal liability insurance, usually stated on the ticket, used to be US$75,000 per pax! It won't be the airline that have to face this one, it will be the insurers, suing the airline for distress etc. is a very long shot as you have to prove the airline is at fault and for that you need indisputable facts, so far there are very few! After all that you have to find a court that will be considered eligible to hear the case and enforce their findings.
Endurance: When estimating endurance based on fuel loaded remember the entire flight probably wasn't at FL350 or similar, there may have been considerable height excursions as well as speed and power changes that will have reduced the overall achievable endurance, 08.11 may well have been just that point.