2016 Transit xlt brakes
 

This van has 39k miles. Noticed from few months in that the back brakes put off a ton more dust than the front. Would make a funny noise when backing up slowly. Took in for recall on the axle. Had them look at brakes. Front in mint condition. Back shot. They stated normal wear and 500$. Yea no. So took to tires plus for 1/2 the price. Well. 6 hours later the back brakes caught fire. I don't blame them since I felt the rear has some underlying issue anyways with the caliper being too tight or the master cyl over pressure to the back. Idfnk. Please offer some elite ford tech insight.

I can assure you this post is not from an elite Ford tech !!
What I might be able to offer would be some possibilities of what could be a cause or causes for the problem and even then without checking the vehicle,,,,,, "shooting from the Hip"!
Some addl info please,
Back brakes caught fire,, which side or both?
Most folks are not aware that stability control utilizes the rear brakes to help keep the vehicle under control in a hazardous situation , so driving habits get into the picture.
You appear to be on the right path with a caliper problem , the question is which one?
If both, possible hose/line restriction, parking brake problem, bearing problem. As you can now see guessing at this without actually looking at the vehicle itself is just that ,Guessing. Maybe some more info might help to get me to the door of the Elite, what do you think?