i think the difficulty in using that hot box (that’s what we commonly refer to those as) is that it is not water tight. it has a gasket and clamps to shut it, but there is no way i can see to use that as a tun or cooler.
if you were doing partial mashes and wanted to keep a small 4 or 5 gallon kettle at a stable temp, then you may be able to put it in that box and it would likely keep it’s temp for a long time.
i can’t really think of any use for the 6" pans either.
you may be better off selling it all and putting the profits towards something more useful. if that box is in really good condition you could get $100 for it.