Yes, Silver, & gold LakenVelders have the Columbian genes, but also like the Brahma are Partridge based, but have extra melenizers.
e^b/e^b, Co/Co, cha/cha, S/S, or s+/s+
Mille Fleur is french for a million flowers. That's the name meaning.
They're pretty much just birds with mottling. Mottling is recessive, & I'm doing my own studies on the mottling gene.
Mottling needs two copies to show. One copy will make splits.
I think there may actually be a dominate...
Columbian color pattern is caused by the genes for the color pattern. The birds you have pictured is Silver Columbian.
Columbian: Co/Co, or Co/co+
Silver: S/S
Light Brahmas are Partridge based, so I'm not sure if the Sussex, & the Wyandotte are also, or not.