Desktop test einviroment setup

Hi all.

I am setting up a test environment for an own repository. For testing i need multiple “Clear Linux* OS Desktop” installs same computer (template laptops with different hw).

I kind of assume i should be able to use “swupd --os-install --bundles=bundleA, bundleB, --path=/mounted_another_root” on each template laptop. But what additional bundles should i add for a similar “Clear Linux* OS Desktop” as from ISO install?
The kernel i will copy from my existing install and configure uefi manually/script using efibootmngr for each /root.
If i do this how will first user be created, is there any onfirst_boot script that prompt on first boot?

Any ideas and/or links to tips how automate/do (Desktop) bundles comparability testing is also appreciated.