There is a detailed list of QML components used within V-Play here http://v-play.net/doc/vplay-group.html
Regarding your components, you will have to replace them with:
Window/PageStackWindow –> GameWindow
Page/PageStack –> Scene
Sliders are available with the GUI plugin for pro users only at the moment
CheckBoxes are currently not supported, you would have to make your own component e.g. with 2 images and 2 states
There are no legal issues with that approach.