Well, now you obviously already have a shell script that does what you need, so anything else is going to be more difficult to use. That aside, I'm not sure that's much easier than using Ansible, however.
For Ansible, you'd need python and Ansible. I'll assume the official iso already has python (it's a full iso after all) -- for ansible you'd need to install it to ram (eg: (optinally virtualenv) and pip install), or modify the iso (say with[1]). Then you'd need a (optionally set of) script(s). Then run that script through ansible. So essentially everything could be the same, but with a lot of the logic of your current script handled by ansible.
For Ansible, you'd need python and Ansible. I'll assume the official iso already has python (it's a full iso after all) -- for ansible you'd need to install it to ram (eg: (optinally virtualenv) and pip install), or modify the iso (say with[1]). Then you'd need a (optionally set of) script(s). Then run that script through ansible. So essentially everything could be the same, but with a lot of the logic of your current script handled by ansible.
[1] https://wiki.archlinux.org/index.php/archiso