vsan licensing question

Hi,

I just read the vmware licensing document and it's really confusing, so I thought about asking here my questions:

1. Lets say I have 10 nodes, but I want only the first 3 nodes to be a vSAN to provide storage. Can I connect the other nodes (which don't have any disks) to this vSAN storage?
2. Do I need to purchase license for the other 7 nodes?
3. Does vSAN export services to non VMWare stuff like NFS, iSCSI?
4. All the examples in the licensing guide shows that I need to purchase for each node 2 licenses, but what if I use AMD EPYC server with 1 CPU?

Thanks