I'll try to write up some steps in a post when I have a chance. I'm not super confident that I have all the prerequisites listed out above as I also have Entware installed with some additional libraries - so if there is someone with a Nvidia card that wants to try out docker support it might be helpful in getting a complete/accurate guide. And btw, I have now tested with Jellyfin with hardware encoding and handbrake-nvenc (only works up to version 1.3 due to the older driver) and both are working in docker.
Yeah, you can go ahead an redistribute if they go offline - I'll also try to fork the github projects I modified to get to the working builds of ffmpeg and libnvidia-container. I would imagine it should also be possible to package the docker addons as an spk - just haven't had a chance to look into it yet.