because the sprite depth is in range [0,1] for the given tile. But the camera depth buffer range [0,1] is used for whole camera frustrum.
If you are exporting 2d images with a depth of 0 to 1, we will call this reference sprite relative depth.
Camera space will use 0 to 1, yes.
So the obvious solution is given a sprite's depth location, we add (or subtract) depth from the sprite location in the camera. So we need a way to translate sprite relative depth into the world. You need to scale the relative sprite depth by the real world depth of the 2d sprite.
If you are rendering a couch and it is spanning 3 tiles in depth, which equates to the orthographic depth range .5 to .7, then obviously your 2d sprite is going to make between .5 and .7
OutputDepth = .5 + (.5 - .7)*pixelSpriteDepth
So the couch is .2 in the depth dimension in length. Your 2d sprite then represents a .2 range in depth values.
.........seems pretty simple, not sure what else you would be asking.