Tilt shift photography makes a real life scene a miniature scene that looks like it is made up with toys, and it is achieved by narrowing the DoF. And, a light field camera captures a scene as everything in focus. So thus can't we turn a miniature scene into a something like a real life scene?
The effect you are describing isn't really narrowed depth of field, but rather a plane of focus not parallel to the sensor. This is often done in macro photography to increase the amount of the actual subject which is in focus — it's hard to get deep depth of field in macro, because you can only stop down the aperture so far. And, yes, you can do a similar tilted plane of focus with lightfield photography. From Lytro's blog:
Leveraging the light ray path information we know where those rays would have been even if the lens settings had been different; focus and aperture for example or artistic lens distortions, or even the angle of the sensor for a virtual tilt/shift mechanism.
But I'm not quite sure what you mean by "reversing" the effect. Can you take a photograph from a tilt/shift lens and turn it into a lightfield? No. But, can you take a macro photograph with a lightfield camera with infinite depth of field instead of choosing a tilt-shift effect? Sure!
No, you can not "reverse" a photo of a real life scene with the "effect" or you can not "reverse" the blurryness of one single macro photo.
But the question seems to be if you can have everything on focus on a miniature photo, then the answer is focus stacking, where you take several photos, changing the focus distance and then combining the images either with specialized software like Helicon Focus. Here are some options: https://en.wikipedia.org/wiki/Focus_stacking#Software or doing it by hand masking zones in Photoshop.
You need to take the photos with a tripod. Some lenses can have some "breething", this is sometimes changing the focus also change a bit the focal length.
But there is another part of your question
turn a miniature scene into a something like a real life scene
This depends on other thing: perspective. You need to have the proper perspective to have this.
This was made all the time in cinema. If your camera is too bulky you probably can use a mirror to shoot from a diferent angle.