For sure get your tires balanced first as aztoytec mentioned, then go from there. I'm in ICT and happy to help if you're still battling the vibration after a balance, shoot me a PM.
I went with the MetalTech hitch as I don't have plans to max out the towing capacity. It's a solid build as expected from the folks at MetalTech. If you have slightly larger tires in your future and plan to mount it underneath here's a heads up. My only niggle is the bottom flange of the hitch...
The 470 xfer is a VF4BM the same as the V8 4Rnr and certain FJC's.
If memory serves the 460's have a different version of the VF4
Not sure on the NV4500 adapter but I doubt anyone has gone down that path yet. Ignoring cost, there are likely OE MT's that bolt up the 2UZ just not in the US.
When you annealed the old washers did you happen to check flatness, sanding them on 320 or 400 grit on glass or granite? Worst case, if the other model engines gaskets don't fit there is always McMaster Carr which has a good selection of metric copper crush gaskets.
The newer units not being centered on the valve tip isn't ideal as a couple others have mentioned.
Since you're exploring overhauling the original rocker arms ask your machinist how they jig up the arms for machining to ensure the plane of the arm pivot is parallel to the rocker arm shoe face...