This may be what happened at first. I can't even remember my exact steps from the beginning because I've fiddled with everything (well, except for RemoteFX).

And I really didn't think that a new...

Ok, that works. But when adding RemoteFX adapter, it stops working.. so perhaps they aren't meant to work together?

But I hadn't even added the RemoteFX adapter in the first VM when enhanced...

Ah, forgot to mention about that, again (also have a post on reddit).

Yes, RDP is on, and actually when using RDP to connect, enhanced session works. But not when using vmconnect.

I have a fresh install of Windows 10 1709 Education N, and using the same image I made a Gen2 VM in Hyper-V.
I thought something was off and then I noticed that enhanced mode wasn't on at all, and...