As previously posted, I ordered part number 84472674 last week; it arrived today and everything was there that is needed for the spare tire equipment. So this part definitely exists and was in stock in my case. Not sure why the sales people and dealer parts guys can't figure this out, because you would think the request for the spare tire would come up rather often.
This is the part number for the kit with the black trim edge on the back of the storage compartment to match the other pieces back there (the "Titanium" version is apparently 84472675) The kit I received included all the items pictured in other posts in this forum - basically everything shown with "Jack & Components" in the on-line parts diagram: jack, wrench, strap, jack container (tool compartment), spare tire retainer, washer & lower support (you reuse the mount stud from inflation kit hold down), plus the storage compartment in black (P/N 84141567 - the big foam piece that replaces existing piece), the wheel (steel), tire (T135/70R18), valve stem and even a label to add for the spare tire size/pressure on the front door jam. You do have to have the tire & stem mounted & balanced as others had noted. Instructions were included that were pretty good (not perfect & small print - but close enough), but you could figure out the installation without them because it is pretty straight forward. I only needed to use a 10mm socket, a T-30 and a T-45 Torx bit to remove a couple of screws. The instructions mention taking a picture/print the SPID label (build label) that is on the existing storage compartment, but this label is no longer provided on newer models (I have a 2019 XT5) - it is now read via a barcode on the front door pillar. There is a fuse location label that should be carefully removed from the existing storage compartment and moved to the new piece (or take a picture/print).
There is a spot in the storage compartment for the Cargo Management System divider (if you have the cargo rails). While I don't think it was intended because it won't be secured down (crash safety issue?), the existing tire inflation kit tucks neatly under the Cargo Management divider when stored.