Perhaps most important – at this point in time – we cannot prove how or when the VS separated from the aircraft. We only know that it did. The rest is theoretical.
I thought we also knew from the BEA that the VS was ripped off FROM AFT. I thought I also read that one of the spoilers had been ripped away by forces in the wrong direction, but maybe I'm wrong. This begged the question of how the aircraft could, apparently, have entered the water tail first and hence my earlier question about whether this was consistent with a spin or flat spin. I guess an attendent question would be how else the VS could be torn away from AFT?