Re #3, #4, might be obvious, but not so by the pilot flying in the situation (good in theory, but not in practice); particularly if the FD is used for 99.99% of operations. The rarity or surprise of the event could reduce the ability to think about the situation or turn the FD off. More so because of the routine of using the FD is a ‘comfort blanket’, its hard to discard.
Extreme situations should be covered by aircraft certification; instruments must not display hazardous or misleading information, e.g. stick shake / push will (should) remove the display - according to aircraft type, …
The in-between area; upset as defined vs ADI de-clutter might have been judged as safe because the information is not misleading - it shows the required flight path, but of course this might not show the approved means of recovery.
There may not be a simple answer, particularly if current industry views on training / operation conflict with previous (outdated) certification assumptions.
But don’t expect pilots to act rationally in surprising situations, nor to plug gaps in certification / operation.
“Most capacities needed to cope with the unexpected are eroded in the continuous attempt to prepare for the expected.
Decreasing staff autonomy (higher compliance to predefined responses) increases the odds that a normal situation stays normal, but decreases the odds for recovery in case of unexpected events.
Surprises are more Surprising.” Jean Paries