Ok, I figured it would be something relatively simple. A weekend away and fresh eyes/brain cells helped!
I'm running a distributed vswitch. Turns out I missed the fact that the uplink port group I created is apparently automatically created as a trunk port.
So I simply changed my (physical) cisco switch ports (that are associated with that uplink port group) from a access to trunk ports, and now all the network tests pass and I have my first working vsan Datastore.
Whew...
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 60
switchport mode trunk