Nice that you found what you needed.
The corner pinning will move pixels in non-full single pixel distances. Which means, pixels will be mixed with each other and the information is smushed. There is no remedy for it, some use sharpening tools after that, which makes it only worse.
Hence why I tried to avoid the Ae workflow at all. But if you oversample, the results should be fine.
I’m not aware if Octane can handle the Offset Y in the camera. (I hope I get some budget next year to get some graphic cards for my mac to see what some 3rd party render can do)
Anyway, sounds like you get closer to finalize your project, which is great!
Let me know if there is anything else, I’m happy to look into it.
My best wishes for your project.