The frame has had me concerned for a while now. It is a completely new environment with characters that are largely original to our story. A lot of the cultural background will have to be manufactured wholecloth as well.
I also agree with those above who have suggested that Harad is a region rather than a singular political unit.
One major problem that could face this season's frame is a lack of focus (the main story has a similar issue but there isn't much we can do about that now).
I've alluded to a solution to this problem a few times prior, but wanted to wait until the hosts were getting ready to discuss the frame again to roll it out.
Rather than focus on a village or a group of "resistance" activists amongst a city, I suggest a return to the season one format, limiting most of our frame cast to only a handful of main characters. This will allow us to generate more personal stories and relationships within the frame, despite only having a few scenes in which to do so.
When Gandalf arrives in this settlement in Harad, he finds that the cult of Sauron, whether covertly or overtly, wields a lot of control over city/ state politics. He also learns that the local warlord is seeking a tutor for his son. This is an up and coming state, and he wants his son to be respected by the other realms in Harad.
Gandalf, trading on the Haradrim's cultural memory of Incanus as a wise old man, obtains the position and begins to tell the son some of the stories we are seeing.
We soon discover that the Mouth of Sauron (MoS) is also present, though his focus is on the warlord himself. Gandalf is doing his best to both avoid an actual confrontation, and to turn his young pupil away from the corrupting influence from the north.
I thought long and hard about Dave’s Task Force X idea, and how to incorporate it. I don’t know if there is time to include additional actiony stuff, but if so… What if Gondor (ruled at this time by Denethor’s father, I believe) has sent a team to eliminate the ruler of this realm, in hopes of destabilizing the region and making it more difficult for Sauron to control it.
Gandalf gets wind of the plot beforehand and attempts to stop it without endangering the lives of the assassins. He fails to do this, while they succeed in their mission.
Gandalf’s protege realizes that Gandalf was aware of the plot, but did not warn him. Feeling betrayed, he orders Gandalf arrested and swears fealty to Sauron through (by proxy of the MoS). Gandalf escapes, of course, probably using the same trick whereby he escapes the goblins in The Hobbit.
As Gandalf is making his way out of the city, his escape is aided by the prince’s servant/valet/batman, who has been present for every lesson. He’s picked up the messages with which Gandalf has been trying to reach the prince. The very last scene of the frame is this young man furtively telling a group of children the story of the duel of Fingolfin and Morgoth.
Even now, in the tail end of the third age, Fingolfin’s duel is still telling the Free Peoples that the Dark Lord is not unassailable. He can be withstood. This also gives credence to Sam’s musings about the dead Haradrim soldier he encounters.