Before moving any further (or specifically addressing some of your questions directly), you need to understand that vSAN has some strict hardware requirements. It's not simply a case of having the networking correct and you can "do" vSAN. You must have compatible hardware all the way around (drives, controllers, drivers, etc.) and configure them in a particular way. If I were you, I'd do some reading up on beginning with vSAN and determine if you have what it takes (or are in a position to provide it) before thinking about redesigning your networks or hosts, because if you don't then it won't be worth it.
and thanks for your reply.
All requirement for vSan are currently respected.