I would suggest using physical RDM as this would isolute storage traffic from standard network traffic unless of course you will be using dedicated storage network. As for the type of network, you always to mitigate single point of failure, ideally you want to two HBA/CNA.
The vswitch you use depends on your license, in general for iscsi I dont think the matters as MP for iscsi at the protocol and configuration between vDS and VSS is same.