My test setup.  Passed through a gpu, keyboard and mouse to the VM.  Played the Fortnite game successfully :-).  While the VM (with physical monitor, keyboard and mouse is still plugged-in) is left alone, I setup a separate pc, with chrome, and used moonlight for chrome, and started the game, again, another success.  

 

I shut down the VM, unplugged the monitor, keyboard and mouse, started it.  Went back to the other desktop, and again started moonlight, all I get is a black screen.  

 

I come back and revert the whole thing, with monitor, keyboard and mouse connected to the VM, started it, and tried moonlight on the other PC, it worked beautifully again.  So I've read that no physical monitor is needed, neither mouse and keyboard, is this still correct?  As in totally no load connected to the GPU.

Pretty sure if you are passing through a GPU, it's up to the card to set the display. Meaning, if your particular card won't start without a display, you need something connected. It's not a property in the VM that is the determining factor, it's the card. You can get a dummy plug to emulate a monitor so your GPU will start.

It is starting.  The only thing is that Moonlight doesn't show any display.  Yup, I guess will just try plugging a dummy plug.

Hi.  Plugged in a dummy plug, and yet, black-out on Moonlight app.  But when using Chrome remote desktop app, I can see the desktop, and perform remote control.  What's wrong with my setup?  Hope someone shed some light.  With monitor physically plugged, Moonlight works.  Without a monitor plugged, it's how I described above.