I like a darker brown I have a Dark Brown Ostrich inlay double setup from Rainwalker for my SoDLE/S5LE the black handles look good with it. I do have a Black SpecOps combat master that my Tan handled Regulator lives in and it looks good too.

Don't think you could go wrong either way so I ain't voting!

Not sure about piggybacking a skelly with the WarDog. The War Dog is small enough that I don't see the advantage of having a skelly with it. Also not sure why you would want the Kydex insert, just more chance to scratch the blade. Go all leather and get a DFLE to piggyback the War Dog on.