Congratulations on the serious haul of new shoe acquisitions.
With regard to Edward Green shoes in the three colors you mention, midnight, burnt pine, and dark oak, it is all pretty straight forward.
Out of the box, I recommend using an ever so slight layer of polish. Apply using a small applicator brush, rag, or chamois/cotton polishing cloth. The idea here is to apply a thin layer of polish as protection against dust, dirt, and the like. Neutral (clear) polish is good, colored polish is fine as well. Once applied evenly on the entire upper, let stand for 5 minutes or more, and then polish and buff using a horsehair brush and polishing cloth. Alternatively, some might subscribe to treating the new leather shoes with a leather conditioner, such as Saphir Renovateur or Bick 4; to this I would say be careful. Because these products are technically leather cleaners, as well as conditioners, they will pull some polish off your new shoes, and can dull the shiny factory finish of new shoes.
With regard to developing or preserving the original color of the leather shoes through subsequent polishes:
(1) If you wish to maintain/develop a natural patina on the shoes, while avoiding darkening their factory finish prematurely through polishing, I recommend using neutral color polish on all three (or any) colors. You could also use polish that is slightly lighter in color than the shoes themselves in the general course of polishing. Definitely use a high quality polish made with non hydrocarbon ingredients, such as Saphir. Apply leather conditioner and edge dressing to the appropriate areas of the shoes as needed when the upper is dry and sole edges worn.
(2) If you want to create a burnished effect through polishing and/or keep the finish dark, or perhaps darken slightly, use color polishes that match the shoe colors. Dark brown for dark oak, medium and/or dark blue (navy) for midnight, and whatever the medium brown equivalent to burnt pine is. Saphir has a color chart that is easy to find online, if you choose to go with that brand, as many of us, EG owners, do.
I am sure other members will make further detailed recommendations that build on what I have mentioned, or contradict this. Please remember two things before following any advice: (i) different people go for different effects when polishing shoes, e.g. matte polish finish, highly burnished/antiqued finish, high shine in single factory color, (ii) pretty much any coloration or effect achieved with shoe polish (and not dye) can be altered and/or removed with leather cleaner/conditioner. It is also worth mentioning, not all shoes in a single colorway, e.g. dark oak, are exactly the same color; this is also something to take into consideration when selecting how best to maintain or develop the color of your new shoes.
Best of luck.