When Hyper-V is enabled, the currently installed instance of Windows is moved into a VM that runs under the hypervisor and becomes a management VM that is automatically started on boot. The management VM does not have access to the RAM assigned to any other VMs. It can potentially ask the hypervisor to suspend or shutdown a VM and possibly tamper with the disks assigned to the VM but only if the ACLs governing access allow it.
I highly suspect the VM hosting Edge will in fact be a Hyper-V VM since most of framework is already there. However this may cause problems with the DRM included in some AAA game titles that currently refuse to run if Hyper-V is enabled.