I was not able to find any reference to this so I deployed some test Virtual Desktops from an image that had EES 6 and ERA 6 agent. I activated EES, made sure it updated definitions, and made sure the correct policy was applied. I performed a test deployment of 10 pooled desktops from this image. I logged into several of them and verified that EES 6 is working as expected. As I logged out, the Virtual Desktops were deleted and more were spun up to take their place. Everything still worked as expected.
Then I logged into the ERA server. Only the original Image VM shows up and one license is used by it. All of the Virtual desktop use just the one license from the image. All of the Virtual Desktops receive updates. I have also tested policy changes and these also update all of the Virtual Desktops. I have the ERA agent set to connect every 5 minutes for testing and the policies updates are pushed out then. On the details for the Computer it gives a subnet as the reported IP address (192.168.1.0). I do not see individual information for the Virtual Desktops but, given they are all exactly the same this really doesn't have much affect.
I use Dell's vWorkspace on Hyper-V. With HyperDeploy and Instant Provisioning, I can go from a Desktop image to 100 desktops in about 5 minutes. Instead of running SysPrep on the image VM, I simply run slmgr /rearm which resets the security ID (SID), clears any system restore points, and deletes event logs.