UPDATE: The huge, gigantic, amazing, colossal good news is that everything is covered by the Ford warranty, thank the old gods and the new. I was told when it arrived at the dealership that they would have to determine the cause of failure before they could make that determination, but the service manager is more of a short-text rather than long-conversation kind of communicator, so I only got the bottom line good news rather than the full findings of the investigating committee.
Ford Explorers have two (like mine) or three or four catalytic converters. When my primary overheated, it melted and took out the secondary, which also overheated and melted. Anyone who isn't living under a rock knows that catalytic convertors have replaced bottle caps as the new form of post-collapse currency, and are therefore rare and valuable, and as the service manager told me yesterday, even more so for me because I have the twin turbo engine. He has already replaced the primary, but the other per his text is "... on back order with no eta. They are an in demand product these days." So until then it just sits on the lot while I drive a rental that's costing me $400 a week. Also since they had time to kill, they took care of the recall items, too (rear toe link, roof rail, and one other that I can't remember right now). I let him charge me $40 to replace the air filter, kind of like tipping the waitress even though you have a coupon for a free meal.
Regardless, I'm calling this one a win. I'll keep the rental another week, but after that I'm begging rides from coworkers. Fingers crossed on a secondary cat converter being manufactured some time before the heat death of the universe.
Side note, I'm seriously considering purchasing another set of catalytic converters and the dreaded water pump just to have on hand against future misadventures.