Hey,
I am the creator of CustomPiOS and came across the distro.
If its being maintained, would love to add it to this section in the readme:
https://github.com/guysoft/CustomPiOS#list-of-distributions-using-custompios
If you like you can also PR it yourself.
Also it seams you are missing the systemctl enable in the chroot_script. Did you ever get this to work?