Yellowish brown and white will make a lighter yellowish brown color. White lightens colors, but doesn't change the hue. It may make it easier to see the yellow undertones when the color is lighter.
Tawny
NO, but ecru is a light greyish-yellowish brown
Yellowish brown.
Color changes from dark brown to a lighter yellowish brown, sometimes rather orange.
Yellowish brown and white will make a lighter yellowish brown color. White lightens colors, but doesn't change the hue. It may make it easier to see the yellow undertones when the color is lighter.
Blonde or pale yellowish to yellowish brown in color.
a yellowish brown almost cream color
yellowish-brown
Tawny
dark brown/black. Fur is yellowish dark brown/black. Fur is yellowish
...Yellowish-White...brown
yellowish gold to dark brown
yellowish brown
Usually buff, or yellowish brown
"Ecru" is a greyish-pale yellow or a light greyish-yellowish brown colour.
I recommend black, to go with yellowish brown.