Although AppArmor is a great idea to enhance security, publishers like Mozilla and Canonical have either not taken an interest or done a poor job of maintaining profiles. So I will be adding (hopefully better-functioning) profiles here, starting with Firefox.
To install a profile on your system, copy it to your /etc/apparmor.d folder and run sudo aa-enforce <profile path>. (You will need to have AppArmor already enabled for your VMs...)