Hey sounds a cool idea… Never done anything like it before, but think you could be on the right track using camera feed render target materials…
You could then get some surreal effects through some funky camera movement so when tilting the card rather than just tilting the camera you also move the camera so it keeps the same focus point but changes its pov…? Would then be pretty easy to create different scenes for each of the cards by just switching cameras…
(tutorial you mentioned & Unreal Engine 4 Tutorial - Basic Camera Feed - YouTube)