the all americans have a heater mode where the dash vents can blow but not the defroster.. you dont want to particularly blow A/C on the windshield.. esp at night.. it will fog the glass up on the outside in humid weather.. it is Nice however to have an A/C evaporator ahead of the heater core for rainy driving..
I built one of my busses such so I can dehumidify with the A/C compressor but still have warm air..
anyway making a kit.. that one gets tough since the manufacturer i got all mine from (except the evaporator in the superior) has gone under..
this is the condensor i used its a ACT CS2, there are others like it..
it uses 2 #8 MOR fittings to attach to it.. the kit you referenced uses a different brand fittings but they chose the same line sizes I did for my build with that evaporator.. i didnt see how long the lengths are in the kit..
you would have to measure and determine a place to put your condensor under the bus.. you want it far enough back you dont pick up too much engine heat.. or plan to cut hole in the skirt and install it as a skirt unit so you suck air from the side of the bus and not underneath..
you also want to find a spot so it wont interfere with items for your conversion like plumbing or water tanks.. then you can scope out how you will route your hoses.. (I used a garden hose that I snaked around so I knew ballpark how much length of A/C hose to order.
compressor brackets - on a FE bus you'll likely need to find a Low mount bracket kit.. I think bracketry systems (unforetunately not cheap) makes one.. you camn contact APAIR.. they have one listed for a 6BT but doesnt mention the 24 valve.. doesnt meamn they dont have one.. you want a Sanden mount kit if you can.. otherwise the standard factory A/C installed by Trans/AIR(still in business) used a low mont kit with a GMC A6 style compressor instead of a sanden.. you would have no issues running that evaporator with an A6...
its hard for me to put together a kit / BOM for you without seeing the whole thing in person as bus A/C is a bit of a custom endeavor..