Create a CD with snapshot of the system after install and configuration

Hello folks,

I pretend install Lubuntu 16.04 LTS in pc for any employer use this pc! I think create an user with, only, permission to read and write, 770.
This is the best scenario?
I think create this user through terminal, because I pretend create a script, and I don't where wizard has install on system for create and delete users!

I pretend disable Lubuntu Software Center, because I don't want which employers can install programs. This is the best shot?

I read, some here which, for a system more security, should change some relative with sudo and su! I can remember well about this! Any have an idea what can or should do relative with the su / sudo for the system be more security?