the lord of the rings - Does the depiction of Uruk society in Shadow of Mordor have any basis in LotR canon?

We already know from the excellent answers on this question that the main storyline of Shadow of Mordor does not make a lot of sense in LotR canon.

But for me the most interesting part of Shadow of Mordor's story is the depiction of Uruk society, which the previous question's answers did not touch on at all. For those who haven't played the game:

• Uruk are led by Captains. The most powerful Captains are called Warchiefs.


• Warchiefs typically have one or more Captains as bodyguards.


• There are five Warchiefs assigned to each region of Mordor.


• When a Warchief dies, one of his bodyguards takes his place, even if that bodyguard was the one who killed him.


• When an Uruk kills another Uruk of significant standing, he may cut off the defeated Uruk's ear and use that as proof of the kill.



• Captains will regularly fight other Captains, sometimes in one-on-one duels, sometimes in larger battles.


• Captains will regularly increase their power/influence by holding feasts, staging hunts for Ghuls/Caragors/Graugs, putting themselves through trials of strength, and recruiting new soldiers.


• Most manual labor is done by human slaves, and the Uruk are--unsurprisingly--extremely cruel masters.


• The Uruk armies are most likely fed by food grown around the Sea of Nurnen (this is the only item in this list that I could find evidence for on the LotR wiki)

Does mainstream LotR canon discuss Orc/Uruk society at all? If so, does it support what was depicted in the game? Or did Monolith simply make up all of this?

Answer

There is certainly a rank of captain in Mordor's army.

By all the signs, Captain Shagrat, I'd say there's a large warrior loose...

(The Choices of Master Samwise)

Some provisions for Mordor's army are provided by slave-worked farms around the Inland Sea of Nurnen.

Neither he nor Frodo knew anything of the great slave-worked fields away south in this wide realm, beyond the fumes of the Mountain by the dark sad waters of Lake Nurnen; nor of the great roads that ran away east and south to tributary lands, from which the soldiers of the Tower brought long waggon-trains of booty and fresh slaves.

(The Land of Shadow)

It's reasonable to assume that the slaves mentioned here are human, though we don't know much about the lands east and south of Mordor. The rest has no basis in the LotR or other Tolkien canon, as far as I know. (You might find something similar in Middle-Earth Roleplaying (MERP) books, though.)