Great start! You'll find out the Ansible VM serves no real purpose as you can install Ansible on the host. Also you could use a YML config file to define your environment. And you should have a look at dynamic inventory scripts.
Useful for testing Ansible when someone isn't ready to install and needs to evaluate first.
A few more comments: you could use pip instead of apt-get for an up-to-date version of Ansible, and you may want to create a Virtualbox share to access the project from the Ansible VM. Also does it actually work? I'm asking because I can't see anything to sort out the SSH credentials.