Support technicians told me that the VSAN datastore would still be available. But that I couldn't add or remove disks to the group. Then said to move it asap because I would lose access to VSAN and it would be in read only mode. Lots of different responses :( Good job Broadcom.
In the end I signed up for the VCF Sphere trial to hold us over until we get our storage network online and I can migrate VMs off of vSAN.