Orc intergration after the War?

[Andsigil]

We're talking about two main branches of orcs, right- those of the Misty Mountains-Gundabad, and those of Mordor?

As far as Mordor orcs, I doubt any of them stayed close enough to Rohan or Gondor after the war to attempt any kind of assimilation in the first place. It would make sense for them to have fled east, where their allies originated and where they, too retreated, after being defeated.

Orcs, being orcs, would then "orc it up" in their new eastern homes, and they would quickly find out (the hard way) that Easterlings, like the Variags of Khand, were just as cruel and genocidal as they were.

As far as the Misty Mountain orcs, I had the impression that most of their power was broken in the Battle of Five Armies. By the LoTR, they seemed to be, at best, a local threat, and probably faded away as a society relatively quickly.