There’s going to be a lot of Sunday armchair QB’ing on this one. My two cents? They were in a stall situation and didn’t realize it. They hit the water almost flat (tail a bit down).
Is it known what the final descent rate was? Still something like 125 mph?
Semi agree. Pitch dark. Ice jammed instruments. Conflicting data from those that worked (perhaps partially, instruments get crazy if sensor ports blocked with ice then starts to melt away).
Wow, that destroys the breakup in flight theory. What was the visibility?
Absolutely. As the speed approached zero the warnings would stop. (The logic being the speed was impossible.) As the plane gathered speed but was still below stall, the warnings would start again. That's very confusing to pilots who don't know what they're doing. And probably confusing to pilots who do know what they're doing.