Используя VMware vSphere с единственным NIC

Q: Is one physical NIC on the vSphere host sufficient for this scenario?

A: More than likely. Technically it will work. I'm assuming that the NIC and switch are 1Gbps and if so, that should provide enough bandwidth for your VM's.

Q: What kind/type of network configuration is suitable on the vSphere host to separate traffic addressed to the guest OS from host management traffic?

A: If you have only 1 physical NIC then you can't separate management traffic from VM traffic, but there really isn't going to be any management traffic, at least none that will impact the performance of the VM traffic. The only management traffic you're going to have is when you connect to the host with the vSphere client to perform some task on the host, such as when creating or modifying a VM.