Henra
Taking this together it does not seem that the depleted energy was the reason for the reduction of the climb rate.
There is only one way how with the data points we have the V/S can have gone down to 700 fpm if speed was >215 kts an AoA was 4°. And that is that the Pitch must have reduced after the initial Pitch Up
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V/S can have been reducedby other factors as well like bank angle / roll to left and right, decaying airspeed, drag by deflected ailerons / rudder.
Concerning AOA: The relationship between AOA and pitch is not factual, theoretically a pitch of 90° with an AOA of 0° is achievable (not in an transport ac, but in a fighter ac).
I did observe lots of misunderstandings concerning unloading (stick forward) in nose high situations after more than 1 g was applied. 0,5 g already feels like a lot of unloading, stops the increase in pitch rate and reduces the AOA somewhat, but doesn´t change the (upward) flightpath immidiately and drastically. To really get the nose travel downward fast (and that is necessary in a nose high low energy state) unloading to at least zero g and below zero AOA is necessary, a vey uncomfortable thing to do if you are not used to it. And it takes some patience to wait till the nose is definitively below the horizon until further actions (like rolling wings level and applying power) have enough positive influence.
So i agree, nose down input had some effect, but not enough (Unload not high enough and not long enough).
Applying TOGA at that point was IMHO the worst thing which could be done by the crew. As long as the nose was above the horizon this TOGA produced a pitch up from the underslung engines and some noise, but no positve effect for recovery. That coupled with nose up stick input kicked the ship straight in to the fully developped stall.
That is no direct blame to the crew at the moment, as it affords training and expierience to act accordingly in a situation like this. A fighter pilot gets lots of training and application of those procedures in daily flying, the stall aproches in landing configuration or in medium altitude for air transport pilots in the simulator falls way short to that demand.
Concerning the somatogravic illiusions, spot on!