Update: SUCCESS! This job took me about 2-3 hours.
To recap, the L-wrench was a dead end. I used a sawed-off T60 bit another poster mailed to me.
The T60 bit was "beveled" and seated very deeply into the star. It fit much better than that flat T60 L-wrench. See photo:
I was able to do everything from above in the engine bay. 12mm wrench on long pipe. For clearance, I did remove the coolant overflow tank. Good tip.
I was worried about stripping to star hole, so I drew a little line across the bolt with anti-seize to be able to see if I was stripping the T60, or if it was turning.
With the long pipe, it wasn't hard to move the bolt at all. I really didn't have to push very hard on the 3-4 foot bar.
I was so psyched to see that the bolt had moved, and not just stripping the star.
I never detached the oil filter, but maybe this would have made it easier. It would also have resulted in less of a mess.
A ratcheting wrench would have been awesome here because it was a total pain to keep detaching the wrench after every turn WHILE pushing the T60 to stay in. Some masking tape/gum may have helped in keeping the T60 in place. What I could have done was to push the OFA towards the block and popped the T60 shaft off the o-ring, and then just turned the entire thing by hand. Instead, I left the shaft seated, turned the entire thing using the T60, and then popped the shaft free once it was detached.
The 2 shaft o-rings did not feel stiff. The large o-ring did seem a big stiff. It was hardly brittle plastic, however. But, maybe it got a little flat. Wasn't sure it was enough to make a leak, but who knows. The new o-rings were definitely softer.
I used engine degreaser to clean all the gunk off the OFA. I will keep an eye on it for new leaks. When replacing the o-rings and degreasing, work with the OFA in a pan, tub, or bin. It will keep spilling oil and soak through towels. I made a mess, but I didn't really lose much oil. When I checked the dipstick, it still said full, so I didn't even top it off. I will check again tomorrow.
It was a real pain to get the shaft rethreaded back onto the block. Instead of fully re-seating the o-rings/shaft onto the adapter, leave it loose, but seat the OFA fully against the block. That way the play is in the shaft, and you can re-thread the shaft by hand (it would be a nightmare to catch the re-thread that shaft using the T60/wrench combo. Even by hand, loose, it still took me 15 mins to get that shaft to re-thread. Once it caught, I was able to spin it 90% back by hand. Use paper towels to maintain grip on the oily screw.
Thanks to everyone who advised.
It feels really good to have this under my belt.
My next train wreck will be the VC gasket!