It would appear to me to be completely fruitless to attempt ANY 'analysis' of heading at impact from the lie of any wreckage. The remains of the aircraft will 'fly' just as well in water as in air, and since most seem to be postulating some sort of rotating motion at impact there is no reason why this should not continue during the 4000m drop resulting in ANY sort of orientation. Until FDR data is recovered, all the wreckage tells us at the moment is roughly where it hit the surface.