I think the main carcass of the truck is the same as a ROWT. Tailgate is aluminum, not sure about the ROWT.
I think they just cut the fascia down enough to get a steel bumper below it and slightly restyled the hood is about it for body changes. They played with the suspension and the frame to mount said bumper.
As far as reusing ROW parts for prototypes, the trucks on display in Detroit had banjo style rear axles (like ROW trucks) rather than the Salisbury style that the spyphotos show taken from trucks driving around. They were very adamant not to take photos of the undersides of the trucks because the production trucks will be different than the display trucks. So as far as "prototypes" go, it is cool but don't put a ton of faith into it being 100% the way it is going to be.
On other have the Getrag MT-82 from the Mustang bolts to the 2.3EB and has reasonable ratio spread. (no double OD, so you would probably be looking at 3.31 axles*, but we can fix that later).
*CAFE comes before performance.
If everyone else can do it with cruder engines I don't think that would be a deal breaker. What would be is if it is worth it for Ford to develop a transmission. MT82 would be a good start... gotta make it 4wd though and the ratios will probably need played with all of which takes $$.
Manual Tacos are SCARCE, I am not sure how Toyota pencils out keeping them in production. And yet they are still cheaper than an automatic which defies all logic when some people will travel all over the country to get "the one".