I'm trying to make a simple scene where the camera is in orthogonal mode with isometric settings just like if it was an isometric 2D game. That's because I have already tried doing it with 2D only but it wasn't possible, so I switched to 3D hoping I will achieve that.
MAJOR EDIT:
Switching to 3D I would like (if it's too complex I don't care) to add a sort of lighting feature in order to make some sides darker or brighter than other sides. In addition to that, I want to be able to rotate the camera by 90deg in 90deg around the player to visualize the scene from 4 different angles.
My scene has to render some cubes (which could also be on top of each other) and make them look like this (taken from here):
Original size image: 
Without any anti-aliasing filter applied, just the pixels... Here's an example of how it should be rendered with other blocks using Tiled:
MAJOR EDIT:
I tried making the cubes a billboard QuadMesh always facing my orthographic camera but it's a very strange way to do this and as the cubes are now 2D billboards at the center of the block, the player gets sometime rendered before and sometime after the billboard based on the position, and that's absolutely WRONG!
Then I tried to make a shader to make a cube like this:
to look like the previous images but it didn't work as I wanted.
I also already tried the shader applied to a 2D image which floors the pixels. Still, the output effect is not what I need, because I don't like the single pixels to be in a fixed position. I want the pixels to be aligned with the block, so when the player moves, the pixels don't get brutally shifted to the new giant pixel size but get shifted smoothly on the screen. Obviously, down-scaling also doesn't work as I want.
Is that possible?
