How could I possibly goof a rear main seal I asked myself. Turns out my only goof was not checking the crank before installing the first seal.
So those 2 blobs of silicone left on the crank were pressing on the soft lip of the seal as the crank spun, just letting all the oil out.
My brother being the ******* MVP that he is came over after work to help me drop the transmission, inspect everything and reinstall it.
Thinking I might email AAM about it but I doubt I'll get anywhere.
Anyway that saga is over. I also solved the intercooler piping issue. I've got some stuff left to tighten under the car, the front end to install and the interior to clean up.
I may strike up the ambition to pull the fuel pump assembly again to see whats up with the level sender.