Tony, lets see if we can ever agree about anything.
Its Thursday, yes?
I agree with 1 the spring pressure is constant, but what pressure is the electric pump going to be?
The diaphragm will be under constant pressure, they are not designed for this.
Leaking diaphragms are very common on old AC pumps, that's why they sell repair kits, the valves are more reliable.
Oil dilution with fuel is common, I've had 2 cars that had had underbonnet fires due to petrol in the sump. Yes, diesel is less likely but still possible to destroy the engine before the OP realises.