AeroTech...
May I be somewhat forward, and ask where you are going with this? You are bringing up some potentially valid, but minor technical points, but missing the "big picture"?
A "safe" "commercial" flight is essentially based on the premise that any single failure will not unduly hazard the passengers. A twin engined aircraft therefore meets this criteria, since an engine failure can be tolerated at any stage of flight.
Having "lost" an engine, this premise no longer holds true. Failure of the other powerplant essentially leads to dead people. They may be lucky, and live, but it should not be down to luck. Therefore, having lost an engine, this risk is minimised by "Landing ASAP".
Fuel Consumption, Cruise Altitude, and "making destination" are 99% likely to be irrelevant. Any Crew taking these into account is asking for trouble.
Again, the EPR is not really relevant. Idling EPR < 1 is theoretically "drag" not thrust, but still less drag than shutdown. EPR has no relevance to producing hydraulics / electrics / pneumatics - these will be more RPM based - and N2 on most engines. On types I have flown, the only time above idle is needed is for pneumatics on the ground to crossbleed another engine.
For a 3 or 4 engine jet, the idle or shutdown will be more likely based on ancillary systems than fuel consumption. I have no figures, but doubt range / Crz Alt etc. are much different between idle and shutdown - the idling engine will (inefficiently) produce some thrust, but use some fuel. Whether it can make destination depends on the fuel plan at the time, and also asks many other questions - see the BA LAX-LHR threads
HTH NoD