Wax is really the only category of Adam's products in which there is more than one product for the same purpose. All other of Adam's products are uniquely important (though not all of the products may be necessary for everybody).
If you have already ordered the Americana wax, then there's really no need to also get the Buttery Wax. They are both Carnauba waxes, though one is paste and one is liquid. Americana lasts longer and gives a deeper wet look, that's what a paste has over a liquid.
The Machine Superwax is more of a polymer sealant and is best used for ungaraged cars that see the elements of nature 24/7 (especially if you live somewhere that encounters all four seasons). It lasts about 6 months, and is great as a base of superior protection which you can then top with a coat or two of Americana to enhance the durability and shine.
As for the other products, like I said, they are all uniquely important, and you can't really rate them against each other. The only other products I can think of are the Fine Machine Polish and Revive Polish. FMP is a mild correcting polish and is used after Swirl&Haze Remover to fix microdamage caused when using the SHR, this damage is really only apparent on dark cars. Revive is a cleaning polish and has no abrasives. Which one you get depends on your car and your needs.
If there are any other products that you need comparing that I may have overlooked just ask.