The wall art looks like a really cool find.
I’ve been in a “road show” reproduction of the tomb of (I think) Seti I, and while the colors were a little dark, basically every inch was painted. The walls of these tombs were left rough, then plastered, the initial carbon drawing of the eventual work was put on, then the master painter inspected and corrected that, and finally the painting was done, basically the same steps used in European fresco.