Hyper, you do realize that diagram is a really good argument for the plane hitting mostly flat and pretty much shattering tossing bits and pieces all over the place, don't you?
If it broke up in the air and spewed people from where it broke you'd see a different distribution, I believe. The broken fuselage with px still belted in probably would not hit hard enough to crack it again like an egg shell. And there'd likely be more px from either near the crack (both sides) or from where it finally broke up if it did. A fairly even distribution would not likely happen.
Yes, there are more from from the rear than from the front. And over the wings is somewhat lightly represented. The px from the front and rear argue for a complete breakup on inpact as the BEA suggested with the wing area being partially protected by the mass of the wings themselves.
If the px in those seats suffered compressed spines then the issue of how the plane came apart is "close" to settled. It had to have experienced a REALLY violent stop from a rather fast vertical fall. If the px had "flail" injuries but few if any spinal compressions from at least one area of the plane then it may have broken up at altitude.
Alas, none of this tells is WHY it got there. It is more data to fold in with "found here on date and time such and such, water currents, and 02:10:34 position report" data to find out what happened. Why and how are very likely FDR and CVR related questions. (I suspect both are needed to pin down precise reasons and sequences of events. CVR is probably more help than FDR.)
JD-EE