Hi,
still I do not know whether the data somehow differs between docker and desktop GUI. Anyway:
Would be nice if the Config Tools installer contained all the needed data
It would mean gigabytes for all processors (almost 500!) and they will become not up-to-date during the time anyway.
offline (don't download anything from internet leading to unexpected build results)
currently there's no direct CLI argument, you can put preferences into the docker image with offline option turned on:

then you can find the preference stored in the $HOME/.nxp/MCUX_Tools/11.0/preferences/.preference.storage4.properties
...
offline=true
...
and this file you can put into your docker container.
Another option is to overwrite the server from which the data is downloaded, but it will pollute the error log with false errors.
See <installdir>/bin/tools.ini and this line:
-Dcom.nxp.restapi.server=https://mcuxpresso.nxp.com
- verbose (so we would see what the tool is actually doing when debugging these kind of issues)
If you want to see more messages in the console, you can tweak the
<installdir>/bin/configuration/logging.properties
and change
java.util.logging.ConsoleHandler.level = SEVERE
into
java.util.logging.ConsoleHandler.level = WARNING
Manual could also describe how to import processor data for non-GUI usage (on Linux)
Yes, you are right, anyway it is a simple ZIP file that can be extracted into ~/.nxp/mcu_data_v11 folder (here for Linux and tools version 11)
Regards,
Libor