Window 10 does not have that much bloatware to it, and most of it is simply removeable via normal means
All of it is removeable via powershell.
having windows 10 stop doing updates is as simple as disabling intelligent background transfer service and windows update service in services.msc
keep in mind that also disables AV from updating, so be mindful of web browsing on such a machine
if one really really wants the pc not to be able to see microsoft at all, i could give you a modification to put in the hosts file
mind you that prevents the pc from seeing microsoft at all, even if you need it to see microsoft for some reason.
Doing so is not really super useful, unless one is telemetry paranoid, and a pincab doesnt generate much telemetry to begin with, if it is even connected to the internet at all.
I cannot answer as to if ghost spectre is useful on a cab or not
I can tell you that in general as an OS, it was utter garbage
So many things flat out did not work, DX 12 was basically forget about it.
There was an annoying number of things that would not install right or run right
Hell i could not even get windows to activate with a valid COA