Q4 as I recall correctly you can only turn off the fluid supply to the engine driven pumps but not turn them off, hence no sense in an overheat indication.
If you turn the EDP off (not pull the fire handle), the pump operates in a "depressurized mode". In this mode, would you expect that the pump is not working as hard, so perhaps would run cooler? According to the Maintenance Manual, even with zero fluid output from the pump (to airplane systems), the pump can still generate a fluid pressure of 2900psi (compared to 3030psi at 3750rpm at 37.5gallons/min in pressurised mode). Whether this slight reduction in pressure indicates a % decrease in work, I can't say.
Note: In depressurized mode, the EDP pump casing is still being cooled with hydraulic fluid. On the other hand, if you pull the fire handle, fluid is shut off entirely to the pump.
It would be interesting to know how much heat (generated by an overheating EDP) is returned to the reservoir and then transferred to the EMDP (where the temperature
is monitored).
Rgds
NSEU