No intrusion taken at all! I'm glad to try and help 'debug' the painting problem you brought up. I think the base coat is 75% of the problem as you've already pointed out. The first photo looks like a set of raw castings which haven't been basecoated at all. Part of it could be the photo not showing the subtle difference between the plaster and basecoat colors though. If you are looking to exactly replicate my scheme you'll definitely need a darker basecoat.

It looks, however, like you are trying to replicate the concepts rather than the exact paint scheme and are shooting for a lighter version. That could turn out really neat I think. I do have a tip that might be helpful. The problem you are seeing is similar to how I messed up my initial try at painting the first floor which resulted in the 'calico explosion' I experienced. After I saw the results of my mishap, I knew I needed to significantly thin the spot washes (the brown, black, and terracotta in your case) with more Future to make the washes more transparent. The contrast and color difference between the basecoat and splotches needs to be far less. Once the contrast is under control, the drybrush step will help give an overall highlight to the piece and make the color differences even less. Finally, the wash (which looks about right by the way) will be able to merge all of the colors together.

You'll especially need to thin the terracotta down (using Future rather than water) since the color is so much more intense than the basecoat. I think the color can definitely work - it just needs to be much more subtle. The up side of having such thin washes is that your paint will go a long way. The downside is it can weaken the glue bonds temporarily until it dries and it will be shiny unless you add an additive or take care of it with a spray dull coat after the piece is done.

Well, let me know if anything isn't clear or if you get a chance to try another test and can post some pictures.

What brand/color of paints are you using by the way?