I have oil that collected all around the bell housing, I can’t tell if it’s from the upper oil pan gasket or if it’s the rear main seal. Possibly the lower oil pan gasket. Any thoughts?

 

Rear Main seal will be a pressure leak, so LOTS of oil will come out while engine is running, i.e. puddle on the ground under it

Pan leak is a gravity leak, like valve cover leak, a bit of oil, drips not a puddle

If possible pressure wash under side to clean off the oil coating
Then inspect after a few days to see if you can tell where the leaks are

Gravity being gravity.................oil doesn't leak UP, lol, so highest point where you see oil is where the leak is, at least one of the leaks