Got this done. The big hammer got it all but 2-3mm away from where it would have been stock. Originally both bushings sit flush on the back side of the knuckle, and a few mm out on the front. This one flared at the end as I drove it in, but I only missed the goal post by a tiny bit. This bushing absorbs a lot of shaft misalignment anyway so I'm not too concerned with it (drives fine). But it took maybe an hour or more of hammering, so sanding and polishing both surfaces helped get this far:
Here's everything together:
I don't have the air spring in the right side yet since I didn't have them when I put that spring in (easy to go back and put it in later since I've already disassembled once).
So driving impressions - this is similar to but better than in 2010 when I put Air Lift 1000 bags in my OEM springs, which helped a lot then. My OEM springs were not broken, but still very soft and bottomed out harshly over everything, upsetting steering in the front even on the highway. These with no bags give a very slight lift (guessing 0.5 - 1.0" but some of that is new spring seats) but mostly a much more stable and firm ride. No bottoming, less squish into the corners or with road camber, better tracking without the camber following, etc. I want the air springs back in for when I'm running heavy loads, but this feels a lot like what I was running usually (10-12 psi) unloaded so I will probably keep them at 0 psi until I put things in.
The Air Lift bags seem to lose their force over time, so 10 psi when new in 2010 does not feel the same as 10 psi in the same bags in 2018 as the bag deforms and squishes out through the coil springs more when pressurized under load. The Moog springs are a better permanent solution.
So now that I have new Bilsteins and the Moog springs in the rear, it definitely highlights the shortcomings of the OEM springs and Rancho shocks in the front. Next up is Moogs, Bilsteins, and the recently released polyurethane spring seat kit from 4x4parts.com for the front
Important lesson learned someone else already pointed out: When you take out the outer coil bucket LCA bolt, lube the shaft of it with lithium grease or something else persistent, and put it in the other way so the bolt points backwards. That way you can hit it straight on with a hammer from the back side of the truck if for some reason the grease isn't enough to keep it from seizing like this. Otherwise the CV joint is in the way, and the only way to hit it directly is to pull your half shaft out on that side (problematic if your truck is already jacked up on one side only...I tried). If I'd been able to do that I might have been able to avoid shredding the bushing, although I suspect that I figured out I was twisting the rubber too late anyway.