It sure seems these have loosened up a bit. I had a WT too and switched to your OBX build but with LUX. Probably depends more on your reservation at this point. I was a first night res and high on my dealer allocation. Scheduled for 8/30.
I had a WT(LUX, Tow, Leather) on order but switched to OBX(SAS, LUX, 2.7, Tow, Leather, Soft). Basically the exact same build as long as you are okay with the OBX interiors. Otherwise, all i lost was the MIC and Baja mode but was able to keep Sport mode. OBX was about $200 cheaper. Just...
Ford does offer rear heated seats in certain vehicles. For example...F150. However, I have not seen anything that says the Bronco will offer them as an option.