Wow, Joe, that looks gorgeous! You did an amazing job! So nice to have a 9W, too.
On the oil question -- linseed oil is derived from flax seed, so maybe it has a tendency to go rancid or oxidize over time. Mineral oil is derived from petroleum and never goes rancid. It's pretty much inert. Any oil will immediately darken the wood some, or at least bring out the contrast in the grain. But will mineral oil turn black over time, like the appraiser said linseed oil would? I don't automatically believe everything the road show appraisers say because I've seen them get things wrong. But I think it's worth looking into.