Glad you brought up the UNIX box I may look at this option for another setup I am doing. Also glad you highlighted the mail as well I sort of had overlooked this one. I think from all the information I have been given within this post I can quite confidently be sure that I will have quite a safe setup.
One other thing I noticed on the parental control software is you are able to view the logs of the created users. This way we will be able to see exactly what type of usage is being made by each of the kids.
