As the headline says, is it possible to configure the sandbox or add the function to make it possible to run UWP apps in sandbox/Virtual Desktop or is it not possible due to Windows own virtualisation of UWP apps?
You can use the metro apps file group to use as an auto-containment rule to run fully virtualized, but last time I check they would crash when run in containment like that. Because they are not normal desktop applications they don’t work in containment.