I am not part of ReactOS team. I am just a user. It was running when I was using Qubes 3.2.
"I just ask because it seems to me that the reactos project would be
perfect for those of us that are forced to run some win apps."
I tottaly agree with you!
"Just curious about if/how much they are prioritizing VM guest support - and how hard/easy that would be?"
I do not know. And the problem is the same for chromeOS and android iso installations.