having a hard time actually seeing the oil mark in the photo's. Is it to the lower left of the turbo oil line in the photo? I would check the oil fill cap for cracks. It's not shown in the picture, but it would be up and to the right of the pictures shown.
You will have to back up the camera for us to ID the linke on top of the turbo oil line. I believe it's coolant. The entire oil filter housing is an assembly, complete with a heat exchanger for cooling the oil. It mates to the engine block with gaskets, which could leak oil, but you would be one of the first on the forum with that problem.
The nut of the oil filter housing is 24mm, and a lot of technicians put this on with 1/2 breaker bars/wrenches. The gasket on the cap just needs to bottom out in the housing. I think the torque is around 12-15 ft/lbs. Less than a spark plug. In a hurry with too big of a wrench, and this could easily crack causing oil to drip down on the turbo.