Third picture,center right is the pulley of the air conditioning compressor.The
AC hoses attach to the back/rear of the Compressor via a manifold(bracket).
Are you saying the AC Manifold is dripping compressor oil?'Could easily be the
"o" rings in the manifold.You're lucky, the compressor on the SD is an R-4
General Motors type that Mercedes used in the '80s.(lots of them made).

A sub-frame bushing is a rubber isolator mounted in the sub frame
that is bolted to the unibody (or Main Frame).It provides stability
without transmitting vibration.

Jim is correct the oil separator system functions well when maintained.

If you will clean out the oil separator and the drain tube(and the cover of
the air cleaner) regularly that little system will function as intended.
It is all part of the emissions control...Early Days the gases from the
valve cover were just allowed to enter the atmosphere.Now the gases
are recycled into the intake along with the oily mist from inside the
valve cover.

In your third picture, the hose with a steel spring cover (just to the right
of the oily oil cooler line fitting)is one of your two transmission cooler
lines.There is a heat exchanger inside the Radiator for the ATF that the
line feeds.