I am not sure what changed, if anything. But:
foreman-installer --foreman-proxy-httpboot true --foreman-proxy-http true --foreman-proxy-templates true
That does not work for me:
curl http://$(hostname -f):8000/unattended/iPXE?bootstrap=1
Requested url was not found
I had to add --foreman-proxy-templates-listen-on both because by default templates endpoint does not listen on HTTP (8000) port, only HTTPS (8443 or 9090).