<Jumps up on soapybox>
Valve cover gaskets, oil pan gaskets and rear engine covers are the most common external oil leak areas of a 3800.
If you have oil or coolant in the valleys of your LIM, it means your LIM bolts are no longer sealed and seepage is occuring. Clean it and see how fast it comes back. Likely you'll give up waiting on it.
LIM gaskets 99% of the time do not allow coolant into the oil. This is a misconception just like the thought that when an L36 UIM fails and dumps coolant into the intake and fills the oil pan, it does not fill the oil pan with coolant.
