On the issue of no 2-door Sahara, and the SelecTrac transfer case only being offered on the Sahara, reminds me of a talk with the Jeep people at one of the Jeep gatherings several years ago.
When asked why no SelecTrac option on the Wranglers, they mentioned that the 2-door didn't offer enough...
RockTrac and SelecTrac don't need to be mutually exclusive. The main feature with RockTrac is that the Part Time 4WD Low is a 4:1 ratio (as you mentioned). The SelecTrac still offers a separate Part Time Low setting/mode that while is 2.7:1, could instead be 4:1. Flipping this around...
Sorry, but these renderings make it look more like the pickup is based off the JK, than the JL. Maybe its just the lack of the mud exhaust port on the fenders? I mean, those pics look like a JK Hard Rock, with a pickup bed kit added.