For instance I tried to help them to switch the internal REPL from Python to Perl - for vain.

perhaps there is a global configuration that you could alter, and "sell" it to them as being a part of the regular system updates (I'd assume somewhere in C:\Program Files\...) :-)
P.S. I assumed a Windows "Terminal Server". if everyone is working on their own 'puter, perhaps your sysadmins might help you with a GPO or something...