LR lateral link is now replaced and the install is complete. Couple things come to mind why I ended up with so much trouble. I probably should have not used my 1/2 drive air impact to back it out. If I could do it all over again I would have PB blasted that rear nut and turned a ratchet by hand to remove.
After getting the nut and nut casing removed I was in the process of getting ready to order the correct bolt when I decided it wasn't necessary to get the fancy OEM bolt as I had destroyed the nut. I was able to replace with whatever I wanted at this point. I went to Advance and bought a grade 8 bolt, lock washers and nuts. I brought the original bolt to match something up to it. Went home, cut the bolt down a little and installed the new lateral link. I did what mema taught us and adjusted the lateral link to pretty darn close to what the original link length was. Will be good enough to drive to get an alignment. After getting the bolt tightened to spec(1 on my impact, couple pulls of the trigger on 2) I then lowered the car slowly on a jack stand to make the suspension travel to where the ball joint slipped into place like a glove.
Unless I get a nut welded to the inside of the frame I'll leave the opening the way it is....now it is surrounded by a few other openings so I don't anticipate the one I cut to amount to any advance degrading of the metal. I also don't drive it in winter. But I will spray some fluid film in there anyway.