It depends what kind of damage the engine has from it overheating. Replace the engine if the damage from over heating, oil pressure repair, and stalling issue cost out weigh the engine and labor cost which it probably wont. It could be something as simple as the wrong oil filter being installed or the oil is low and needs to be topped off. It sounds like none of these conditions you mention are related so each one will need to be diagnosed seperatly driving up the diag cost. Is the oil leaking on the ground? How many miles on engine? People overheat engines and dont always have to replace the engine luckly.