Hey you can see the level sender sticking out with a single pole electrical connection, and the oil pressure sender just north of it. a trail of oil if leaking will be directly below the location of each. It is the O ring that typically needs replacing on the level sender, many just replace the whole unit IF you are dropping the pan. And IF you drop the pan, it make sense to do the sump screen and suction as a while you are there job. If the pressure drops below 1 bar, and is OE, best to replace that too and the metal washer.
A general review while you have carnal knowledge under there is good. Cleaning and replacing things, check Idler Arm and all other suspension issues. Look for PS hose leaks etc and clean as you go...replacing what you have. By now all the corrugated heat shield is coming off the wiring along the cross member, have a go at replacing that as well.