We don't deal with vehicles such as your mite on a regular basis around here, so information regarding a brake swap is not something we have on hand.
However, if you will post some pics of the axle end and spindle assembly on the mite, maybe we can make some suggestions.
The axle is similar to the unit used on the 2wd pickups of that era (l and s models). I do know that the oem brake backing plates on those axles are kinda "different" as I had a set here until a few weeks ago that I was investigating swapping onto a much earlier version axle in order to achieve a hydraulic brake setup. So I know what they look like (kinda!).
Whatever components are chosen for a disc conversion, it's gonna involve some custom caliper mounts. The spindle configuration used on those axles is nothing similar to what is commonly found in the street rod world which use early Ford hydraulic-pattern spindles, I've already gone down that road extensively and it simply is not doable in a bolt-on fashion.