Privacy settings beyond the front page

I am creating my site for students to use and am required to protect their profile information and engagement within the site. Is it possible to allow a visitor to the site to see the front page but nothing beyond that?

Along that line I also need to validate/approve all memberships with a university email address. Are there any plugins which would automate this or is there a way to moderate approvals of new members?

Thanks for your help. You guys have been great!

-Bill