Update: 3 days later... SUCCESS! All 4 ends out. The answer was LOTS of liquid wrench, a fair bit of hammering and a propane torch. But most crucially : leverage.
I didn't have a mounted vice so what I did was utilize the pushbar on the 80 itself. I wedged a pipe wrench underneath a section of the bumper, used that to hold the rod in place while i had a crescent wrench with a 3 foot pipe on the TRE and reefed on the thing with my entire weight (sounded like a machine gun as the threads broke loose).
One broken wrench later, all 4 ends are out and it looks like the threads are nice and healthy, despite a bit of rust.
Ill upload some pics later.
Thanks everyone for the help!
Now to put it all back together, hopefully with less hassle.