Are you sure about CC not being in their seats ? Of the 9(?) CC, how many have been recovered ? You would think that the flight experienced some progressive roughness before 'whatever happened' so wouldn't everyone be seated ?
You would indeed had there been progressive roughness. Hence the loss of control was sudden and catastrophic.
Amongst the debris recovered were a set of 2 CC seats. Pretty much intact. Empty. And harnesses retracted / unbuckled.
I did the math a while back. From memory, they recovered 4/9 CC, 1 Captain, and 45/216 pax. So they recovered a disproportionately high percentage of the CC. Sure, this could be due to chance. But there are two factors which should lead to finding more pax than CC
a) CC are secured in more substantial harnesses than pax (shoulder straps in addition to lap belt)
b) Without being disrespectful, CC are likely to be closer to their ideal weight than the average pax (younger and thinner). Hence the average pax would be more likely to float than the average CC.
So if everyone was the same pre-crash (ie belted in), you would expect to find an excess of pax. Instead we have the opposite. This makes me think that loss of control was sudden, some people were already strapped in anyway (mostly pax and hence not recovered), and the CC were mostly recovered as not strapped in.