Hi,
Yesterday I was able to pxe-boot a host with the autoinstall (cloud-init) mode from the live-server iso.
I also have templates for preseed-pxe-linux, user-data (autoinstall), netplan-config and partitioning table.
Later today I will share what I have done in order to make it possible.
But it is for sure that additional work is needed in Forman to make the necessary files available in order to perform the full autoinstall.
Beside this, I still need to find out how to apply the install/config of puppet, subscription key, …
All this is done in Foreman 3.0.1 Katello 4.2.1