As for the backup, you can certainly manually backup or use in guest backup like Windows Backup. I just wanted to mention it because a lot of people don't think of this.
Regarding provisioning, it depends on the workload like I mentioned before and also depends on how you configure the VMs. If you have one 4 core CPU and configure the VMs with 4 vCPUs you may soon run into issues. However, if you configure the VM's with 1 vCPU (or maybe two for individual VMs) it might be possible to run 10 VMs or more without issues. Whatever you do, remember that the host also needs some resources.
André