All an excellent idea, fully in keeping with the CSSU idea.
May I add that the bluetooth tethering is a standard option in most mobile phones now, it should have been packaged and on the repos or hand packed as a .deb at least but including it in a late-game CSSU would be cool too.
there are also other SUPL servers more privacy oriented than the google one. https://libredd.it/r/privacy/comment...ageos_in_2019/

It would also be possible to build a custom ready to USB flash CSSU image. I am not sure why that never became a thing and we have been hanging on the old Nokia builds.