The basic foot troops will all be metal.
Some of the larger models will be Resin (Trolls will still be metal), such as the eventual Fell-beasts.
Even though I will likely never be able to produce licensed Middle-earth miniatures, for all intents and purposes (for all your tents and porpoises - sorry.... couldn't help myself

), these miniatures are intended for Middle-earth.
Eventually.... I will need to do Mordor Orcs, and some Early Third Age Orcs for Angmar/Carn Dûm. The basic form would be similar, but facial features, and minor proportions would change.... Such as slightly longer legs for the Late-3rd Age Mordor Uruks, and more varieties of the smaller Snaga Orcs. And perhaps faces that are a bit longer for Mordor Orcs, with slightly different noses.
Oh... And let us not forget the eventual Uruk-Hai themselves. They will be noticeably different from both the Hithaeglir and Mordor Orcs, with even longer legs (but still shorter than humans), and slightly more upright posture.
As for Easterlings, Haradrim, etc.... I have not got so far as the Later 3rd Age people's, only the Mid-3rd Age (from 1800 - 2000 Third Age, during the period of the Wars of the Wainriders with Gondor).
So all of my "Easterlings" are just the Wainriders, with a few Rhûnnic Cavalry, and native Eastern Rhovanion traitors. And the Haradrim all I have are a few shield designs.
I do have a plethora of sketches for the Gondorian forces of this period though.
You will see some echoes of Weta's design elements in a few of them, but overall, they are a significant departure from the film, being armored in Chainmail, with almost no plate at all (The Chivalry of Gondor will have some arm and leg armor that is plate). And the Fiefs will provide mostly unarmored Spearmen or Skirmishers (save for the SE fiefs, which seem to be relatively wealthy).
But.....
Unless I wind up with something insane in a kickstarter like the Conan one with $3m, it will likely be next year before I can get the work done on the non-Orc peoples.
MB