How to make in-progress sprites have blueprint graphics?

In my game, every placeable object and structure will only be placed as a blueprint, which the characters will then automatically build.

An example from "RimWorld":

Objects placed as blueprints:


Objects when finished:


My initial thought was a shader of some sort, where we’d take the thickest black lines and convert that into the blueprint outlines. However, I have no prior experience with shaders so I don’t know how to do this.

The second option is making a separate blueprint texture for every single object which seems very tedious.

What’s the easiest way to implement this? Other than the mentioned options, is there any other way of doing this?