my hints about the path to the *.pro file were really important! This has been the source of your errors all along.
Qt: switch to shadow build in command line -> qmake.exe with path to pro file from project folder
V-Play: switch to shadow build in command line -> qmake.exe just with pro file from the current shadow build folder, no path (because we copy the pro file to the shadow build folder and pre-create the structure for deployment of assets and resources!)
“file:///C:/Data/Programs/%7B3EE0499E-48EA-4C50-8D92-9999CD1CAB1E%7D/Install/qml/Main.qml:-1 File not found”
-> this results out of the fact that you used the pro file from your project folder and not from the shadow build folder, which messes up your dependencies for V-Play projects.
Regarding packaging the precompiled shaders, I will post it in about half hour when i arrive at the office 😉