Understood but I would be very surprised if the aircraft was significantly different in any important way from the sim. If the model is realistic enough for general handling and engine failures on a ZFT conversion, then where are the problems?
You’re well within the tested flight envelope, as opposed to deep stalls, transsonic dives, spins, etc. It’s the same airframe just lacking in thrust. Makes the sums easier: just lift, drag and gravity now!
The thrust is not the only difference. You've depleted the hydraulic pressure on the 737 by the time the flaps reach 5 and you're left on manual reversion, need for alternate flap extension, standby electrics and manual gear extension.
Yes but that should all be taken care of in the simulation. If it accurately represents what happens at the system level when you shut down an engine, as it has to if it has any kind of certification, then losing all the engines should produce a result with similar fidelity. After all, the sim does have to model what works or not when the engines aren’t running as that’s the way it is before you start from cold or after you shut down...