It’s worth mentioning that in French, there’s a distinction between a château fort, and a mere château. I’d translate the first as the English “castle,” meaning a fortified outpost of the medieval period, while I’d call châteaux those confections on the Loire. These days, of course, damn near every winery in France calls itself Chateau this-or-that, and some of these châteaux are nothing more than glorified warehouses.
The Biltmore Estate? I’d simply call it “palatial” (or maybe “baronial”), as someone mentioned above. In other words, it’s neither a palace nor a castle.
Would anyone know what Biltmore might sell for, furnished as is, on the open market today? Just ballpark. Millions? Maybe tens of millions? I’m not sure how you value things like Napolean’s chess set.
I think tens of millions is probably very low. Of course, it assumes a pool of incentivized buyers, of which there are probably very few, but still, it would probably go for a hundred mil or more, easily.