To answer your questions: (Note: I am not very familiar with the CUCV, although I am assuming several things are common no matter what vehicle your working on. For specific items you'll have to ask someone who is more familiar with the CUCV)
-To remove your leaf springs, you will have to undo the u-bolts and take off the top plate. Then undo whatever connects the two ends (one is fixed, one has the shackle) in order to remove the whole spring pack. Then there is a "bolt" that holds the spring pack together that you need to take apart. One end is not hex, rather it is round to serve as a locating pin when the spring pack sits on the axle perch. Then you can work on each individual leaf. Make note as to how they are stacked, and in which direction. Sometimes spring packs are non-symetrical.
-The Slip Plate, and the stuff labled under the John Deere name, don't say on the can "can be used for automotive leaf spring lubrication", but it eludes to it. It says the graphite lubricant paint can be used on any machinery or metal assembly that has surface to surface contact, i.e. car hinges, tail gate bolts, chains, wire rope, shovels, etc. I think its a great use for painting the leaf packs.
-I don't like to use Teflon plates in between spring packs. First off you have to drill the leafs (spring steel is NOT fun to drilll, lol), then you have to buy some teflon and fix it in between. These will wear out and/or fall out. Second, the contact surface area is only as big as the peice of Teflon you put in, with the Slip Plate, the entire surface area of the spring is acting as a friction modifier. Even if you did decide to put some plastic plates between your springs, I wouldn't suggest using Teflon. Teflon is very slick due to the fact that it self sheds its molecular structure. Due to this property it is also very maleable and basically, will wear away rather quickly. When in a dusty and dirty enviornment (like what offroad rigs are in) Teflon will also collect material and imbed it in to itself, now you have an abrasive surface, not a slick one. I don't like using it for bushings and bearings when I don't have to. Something like UHMW or a harder ABS plastic would be a better fit. UHMW has a very low coefficent of friction (its very slick) and it does not plasticate (deform) as much as Teflon. There are other plastics out there more well suited for this application. I work with many types of plastics such as Teflon, UHMW, Delrin, and Rulon where I work. Personally, its just my opinion, I don't like the idea of Teflon or any type of wear plates between the springs. I just don't like them.
If your going to paint your springs, then you might as well just paint them with the graphite lubricant. Kill 2 birds with 1 stone. I have not ran my packs long enough to judge the wear rate of the paint lubricant, but if it did wear all you would have to do is spread the leafs apart a little bit while they are still on the vehicle, and shoot a little more graphite paint in there.
I don't know what the CUCV suspension is like, but I can tell you that the M-715 springs are FIRM. I mean like suspension movement of maybe 2 inches at full load, with a max articulation of 4 inches, lol. So for me, I needed every amount of reduction in surface friction I could find, let alone the removal of one spring to ease the spring rate. If you just want your springs to not rust, then you probably don't want to spend all this work and time doing what I did. I hope this helps.