custom menu question

i’m setting up homepages for a bunch of people in our department. instead of managing a bunch of wordpress installations, i’d like to have just one. so the urls for homepages might be something like:
http://people.foo.com/mary/
http://people.foo.com/john/

and underneath each of them will be things like /mary/publications.html or /mary/contact.html or whatever. the two things i’m having trouble with are:
1. if someone goes to /mary, or anything underneath that, i only want them to see a menu of mary’s pages.

2. i want only john (and maybe a few people he grants access to) to be able to edit john’s pages.

i’m using the role scoper plugin for 2, and for 1 i put something like the code below in the theme’s header.php (i’m also using this as a chance to learn php). my question is: are these good ways to do what i want to do with wordpress, or are there simpler alternatives?

[Code moderated as per the Forum Rules. Please use the pastebin]