If the water pump was broken the car would overheat on the move not just parked up as you'd have no movement of water around the system.I'm sure the Escort had the better water pump, metal impellors not plastic like some Fords.

Sounds like the rad is causing the problem if the wiring is ok to the Fan switch & they had tried to fix a leak previously. Does the bottom water hose get hot after a run ? It should do, but just not as hot as the top.

My fan's come on when the needle is just over half way on the gauge if that helps.