Thank you for your post and sorry for the delay in our response.
Actually we have never installed CG in a HyperV 2012R2 VM but it should work in theory as CG has been validated with previous HyperV versions.
Also CG v1.2.2 is based on a Linux kernel 3.10.100 and according to my information that kernel works well on a HyperV 2012R2 VM. If the only issue you encounter is the detection of your NIC try to attach another type of emulated network adapter to your VM and try to reinstall CG.
Please let me know what is the emulated network adapter that CG can't detect.
IT Technical Architect