I am neither familiar to a great extent with the FBW architecture of the Bus , nor the 777. However, from what I understand it operates ( without Autopilot engaged ) in a form vaguely similar to CWS on my "steam driven" 737, I.E. the aircraft will more or less maintain the same angle of pitch/bank, and within certain limits , return to same if disturbed.
This being the case, given that they had already attained cruise altitude, unless whatever catastrophe that occurred interrupted electrical power such that power to the FBW was disabled, any discussion involving the autopilot is without value, as the aircraft would have continued in controlled flight anyhow until fuel exhaustion.
As a footnote, I think more is known than is being released (particularly radar data) & find it difficult to believe that Satellite data etc would not be available.
Having said that, it took from 5 days to 2 years between finding surface wreckage & anything useful in the Air France accident, so don't hold your breath.