That leak
Once again, apologies for my non-professional perspective.
There seems to be an emerging trend (omitting for the moment the foul play options) in the analysis presented by knowledgeable commentators here which would tend to suggest that the locus of failure was somewhere at the rear of the aircraft, adjacent to the pressure bulkhead and stabilisers.
At the same time several photographs have been posted of this aircraft exhibiting very conspicuous hydraulic fluid leakage in the same area, extending - or so it looks to me - to a seam encircling the fuselage. Now back in the day when I operated and maintained heavy earth-moving and mining plant I'd have regarded a hydraulic leak like this as warranting a repair asap - on a bulldozer, much less an aircraft.
Having read most of the posts, including some which have been moderated away, there doesn't appear to be any informed comment suggesting that there may be a correlation between this manifestation and the accident. Which seems pretty surprising to an observer.