I'm starting to dislike myself for buying this project car.

I was able to fix the pressure sensor issue. There was a bad solder joint on the wire. While there, I also noticed that the cable for the oil temp sensor is missing in action. I will have to take care of that eventually.

About the coolant leak. Two days ago I filled up the coolant tank and I havent lost a drop since then. Today I let the car run, and about 10-15 min in, it started leaking from the front-middle of the oil pan. One big drop about once every second or two. I also noticed some water leaking from where the exhaust pipes connect in the middle of the car as well as out the back. This was after a pretty hot day, so it wasn't condensation buildup.
I checked the oil cap, and there was some milky buildup there.

What am I looking at? Bad head gasket, oil cooler?