A lot of "Oh look at the bird!" moments apparently. Well 3 months after I first started mocking up the rear bumper, it's welded up. Not stuck to the frame yet, but I at least finally made progress.
...the DA really is the cherry on top.
I farmed out the forming of the bumper wing thingys to a buddy. 5 minutes of work for him on a hefty 50+ year old break, was a lot better than me making a relief cut, check, tack, check, weld. I did plenty of that on the 'ol FJ40. Originally I had spaced the bumper 3/8" below the tailgate, but ended up kicking that up to 1/2". Gives a bit more clearance between the rear quarters.
As far as mounting to the frame, I'm torn between welding it directly to the frame (simple) or using similar brackets to all other first gen rears to bolt to the frame. Either way, the side wing things will be braced to the frame, either welded directly or using tube flanges, to prevent them from becoming one with the sheet metal.
Recovery points are on the table ready to be stuck once I figure out mounting.
As well, I've replaced the throttle cable to remedy some sticking I've experienced. The outer shield had melted in a few places and while I don't think that was causing the sticking, it probably didn't help.