I think this is highly unlikely. For one, The train is being constructed to actual scale with an interior and an exterior. There is simply no place for multiply layers of screen...
I agree that this multiplane method could be difficult to achieve because of the lack of space. But I still think that, unless the issue of shifting perspectives is addressed when using lenticular technology, it would be be a jarring and inauthentic experience. (Now if head-tracking technology is used to alter the imagery according to the movement of each passenger, then lenticular tech would work beautifully. This video shows an example of creating a false window using headtracking
[video=youtube;V2hxaijuZ6w]http://www.youtube.com/watch?v=V2hxaijuZ6w[/video] . )
PS: The OLED video adds proof to my point about perspective being unnecessary for the lenticular windows. If you watch the real city behind the OLED said:But that camera is quite a distance from the window in that video. Passengers on the Hogwarts Express will be sitting only a few feet away (only a few inches for some) from the window. Test this out. Stand five feet away from a window and move your head only slightly from side to side. Even minimal head movement effects a change in the position and content of scenery. Parallex at work.
OLED is cool said:If the transparent OLED screens are able to create opaque imagery, then there is no reason why the backstage area of the parks would need to show. The screen furthest away from the window would portray the sky.
I agree with you completely that the tech would be perfect for the frosted effect during the dementor attack, particularly with the inside cabin windows. I posted this theory in the Secret Stash thread a day ago.