I haven't had a chance to look at it yet. Is there a virtual wifi created anywhere in Windows? If so, I would check if that is set as public or guest or whatever network. Also check firewall is allowing through virtual wifi or whatever Windows applet the Android VM is using. Although if some Store apps are working, that may not be the case. Unless sideloaded apps are somehow assigned a different IP?
Maybe, if that is not working - and this is just a guess without much thought - could you find the virtual IP and forward that through your router?
I recall some time ago that i set up a bunch of VMs for a customer using virtual box and something similar happened. I think I solved it in Windows with the firewall.