HostBill installation is fully automated and takes just seconds, more info at Installation
Proxmox v2 module allows you to use NoVNC console. To enable it, copy file _upload_proxmox/vncconsole.html from module directory and upload to your Proxmox servers into directory:
/usr/share/novnc-pve/
Now your customers will be able to access noVNC console.
Important: Make sure to install valid SSL certificate for your Proxmox server, otherwise your customers will not be able to see noVNC console.
Setting up IP provisioning
IPAM module for HostBill can interact with ISC DHCP server that you can install on your proxmox host. With that you can automatically provision/assign IP addresses!
To learn more about it visit Configuring DHCP for IPAM