Yeah nailing down the part numbers for these is really difficult online. I found the part number myself from the website I sent earlier and then just went ahead and took a chance on it. I purchased the part from Tasca as it was much cheaper than the OEM type sites.
https://www.tascaparts.com/oem-parts/ford-seat-cushion-heater-jl3z14d696h ... be aware it says it does not fit my 2018, but I just ignore that because all of the websites are conflicting and I can confirm it is an exact match for your seat as it is identical to mine.
As for the element appearance. There are two of them, one for the bottom seat cushion and one for the back seat cushion. The part I sent pictures of is only the bottom portion but it definitely appears like it is for both the bottom and the back but it is not. I have found no one who has had the back one fail, though I have heard one person replaced it when they did the bottom part, but I have never seen evidence that the back one fails so I would avoid messing with it. Each heater has its own cord. The bottom heater has a green connector on the end of its cord. I believe the top one is a yellow connector. To firmly answer your question, the photos are only for the bottom element, and only APPEAR that they fit the whole seat, the scale of it is deceiving.
Side note, I found that a set of metal picks are massively helpful in quickly disassembling and reassembling all of the plastic snaps and hooks that hold the cover to the cushion and the cover to the frame. Using a straight pick allowed me to easily separate the orange cushion clips from the blue plastic cover rail without damage to anything. Here is a link to the Harbor Freight pick set I have that I used.
Amazing deals on this 4Pc Mini Pick & Hook Set at Harbor Freight. Quality tools & low prices.
www.harborfreight.com