Shape of tail debris
Fewer comments since tail raising on shape of debris than on search methods and batteries. More than anything the tail section looks like a paper bag popped open except for the fuselage face that impacted the surface which fragmented. Pics/vids in situ showed the section retaining some shape which has largely been lost in raising and under gravity out of the water. If other fueselage sections split similarly the large skin sections would have acted like sails in the current while sinking. I've looked at a lot of accident debris (though many fewer with water impact) and such large contiguous skin sections of 8501 laid open seem rare. Question whether the next section forward is found to be similar. Whether a flat belly flop, or a nose-first air compression of aft fueselage, or any other impact attitude still very unclear.
BJ-ENG's post on G's vs human body damage applied to public pics so far suggest lower end of G scale.