I thought a lot about how to texture the reconstructions and making them look good, while also making it clear, that they were reconstructions. My solution is displaying a wireframe over my reconstructions with textures.
For this to work, I copied and pasted both my coffin lid and box. I renamed these copies and after selecting all faces, I went to Face –> Wireframe and chose the settings: Thickness= 0.002, Offset= 0.001, Boundary and Replace are checked.
I then gave these wireframes a new material (blue with slight emission) in the shading workspaces to contrast the textures of the “normal” reconstructions (Image 1).
The “normal” reconstructions I textured with the stencil method (https://www.youtube.com/watch?v=lO8qDNZf5o0) I first unwrapped the coffin lid and box (and made sure to check the scale beforehand) then went over to the texture paint workspace and used wood and plaster textures (from https://texture.ninja/ and https://www.textures.com/). I used these textures as stencils to paint them on to my reconstructions. I used the straight ends of the stencils as borders, so I could show the build if the model (Image 2). To achieve this, I deletes a small part of the model, which at the end shows just the wireframe, another small part, shows the base color white, so a untextured model, and then I added the wooden plank structure for the box and one side of the lid. On the other side of the lid, I added the plaster texture, to show the coloring, that the original coffin lid part at the top of the coffin has. This way, the textures show how the coffin could have looked, and also the modelling of the coffin as a 3D reconstruction (Image 3).