Hi Jerry, hi Claude,
you are putting a big responsibility on my shoulders!!
Claude is right regarding the colours of the sandstone. Look at this site
http://www.carriereschauss.be/de/produits.html It is the quarry where my parents got their material from when they built our house.
As you can see, the material is light in colours.
All in all, buildings made of sandstone would almost exclusively have been churches or official buildings like town halls and schools back in those days.
You have to remember that the Ardennes always were a poor region (and stil are in comparison). All the Luxembourgers who emigrated were from the Ardennes, not because they didn't like the view, but rather because the soil was not that fertile and there was hunger from time to time. Without any prospects, many people just had no alternative.
Fachwerk is generally not the type of construction you will find in the Ardennes, but the closer you get to Germany (east of Eupen towards Monschau) the more you will encounter.
People in lux and belgian Ardennes were rather poor and used whatever material was cheap...and that was slate. Look at Claude's diorama and you will see what I mean.
Sandstone means that the slabs have to be cut by hand and are thus expensive. My grandfather had a business for facades and plasterwork..and his house was (and still is

) built from slate.
Should you want to stick to the lattice/sandstone version, you should follow Claude's advice and lighten up the colours a bit (a real shame bacause I love your palette!!!!) and above all add a step in front of the door.
I would not leave the lattice part in these colours either. This is "nice" modern lattice, with walls and wooden beams set apart in chiaro/scuro

. This was certainly not so in poor regions with rough climate. The beams would be weathered to grey, and the walls would be dirtier.
Apart from the above, I love your stonework. It looks fantastic and I would welcome it for mid- to southerh Germany anytime!!
Cheers
Romain