How can I re-Install a site I pulled in from a git repo?
If you see "it works", Apache hasn't recognised index.php - either you are being served files from the wrong directory, or Apache isn't configured to use index.php as the default file in a directory. You can test the latter readily: http://dev.foo.com/index.php will show the correct page while http://dev.foo.com/ will display "It works".
mysqldump, backup and restore, PHPMyAdmin ... whatever tools you have available.
Yes, you need a working DB locally to install Drupal. And you need the values in settings.php to work to load your existing DB.