Sure leidenfrost is a fine model to use when thinking about food sticking to your pan and preventing it etc. It still has nothing to do with when you add the oil though.

No cooking oil is going to appreciably oxidize in the 70 seconds it takes to heat a pan. I cooked at very high levels for many years, I have seen a cook get fired on the spot for handling a pan incorrectly, no one cares about whatever oxidation is happening during preheating. The advice to add oil to the hot pan is so you don't forget and overheat the oil, or start a fire.