I havent had UnRAID for quite a while now , so can't help with the GUI. It's a parameter for docker. Maybe it's under advanced? If not hopefully someone else can provide a bit of detail.
You have whitelisted a specific IP range in Transmission, but Docker containers use another range internally. Maybe you also need to whitelist the internal docker IP range. I did that and got it working.
User nobody could be fine, if that user has the needed rights to the download folder. You could try going into the prompt of the container and see if you can write to the download folder.
Easiest thing to do is to leave the download location as is in Transmission and change where it maps to with docker. If that gives you rights issues you will need to check rights on the folder and make sure the docker user maps to an actual user (UID GID in docker).
Did you map the /data path to something outside the container? If you did that and then get the Permission denied error you probably need to set the userid and groupid in the parameters for te container (or you used the example ones but they don't match for you).
Check out this information: https://medium.com/@mccode/understanding-how-uid-and-gid-work-in-docker-containers-c37a01d01cf
Hope it helps.
I have never tested with ipv6, so I wouldn't be surprised if that doesn't work. A.f.a.i.k. all the firewalling etc that is done is only done for ipv4 so I imagine quite a bit would have to be done to get ipv6 working. b.t.w. All the vpn stuff is taken from a binhex image.
Just copied the config you posted above in the default config file and pushed the change. This will trigger a new image build.
The side effect is that flexget is also updated to the latest version.
Yes, the config file has to be made by hand to have flexget do anything useful, and be aware that creating a config file is tricky business. There is no gui for the config.
Depending on what you want to do flexget is probably not going to be user friendly. That being said, check their website for examples and details.
Sorry, there is no feature in the docker at the moment to specify a version. You would have to create your own version. If I mess with the scripts again I might have a look at implementing that.