-> Just out of curiosity , can this be done with SR-IOV too ?
You can assign Virtual functions of a SRIOV nic to a VM . SRIOV enablement depends on nic capability/support.
Howabout , mapping one pNIC to a vSwitch and connect it to vmnic through a portgroup. In this case he needs 8 vSwitchs for the 8 pNIC.
Yes.
Are there any particular differences between SR-IOV , Passthrough and above method ?
SRIOV is creating multiple virtual function on a PCIe card which has limited capability. Passthru is directly assigning the PCIe card to a VM. Above method uses VMware network stack.