I have a hen that's a gold penciled hamburg x dark brahma. That comb sure looks like a walnut comb which would be the result of a wyandotte x brahma.
This is her.
The markings on him make me think silver based. Light feathering on the feet could be from the brahma. Silver laced wyandotte x dark brahma would be my guess for the coloring, comb, light feathers. HOWEVER, dark brahma roos are black breasted, silver head, back, saddle feathers. SLW are marked the same hen and roo. The lack of black breast....hmmmm.... running it through the kippenjungle genetics calculator (both ways sire and dame).....very possible.