You can disabled TTY's by removing (or moving to something other than .conf) the following files:
I found the culprit to the auto-login: In the /etc/init/tty1.conf in the live session, there is this line:
exec /bin/login -f ubuntu < /dev/tty1 > /dev/tty1 2>&1
This makes /bin/login log in as "ubuntu" - which has no password set. So, if you want similar functionality, blank the password for an account and set it to log in as that account. Of course, this is generally not recommended unless you're in a live system as it leaves a gaping security hole (unless that user is severely limited).
Also, every time that process it killed (i.e. via
exit) it gets called again - which again logs in as the "ubuntu" account.