I know these things tend to be fuzzy when the Klingons are involved, but...is being directly involved in the death of a high-ranking Klingon a Prime Directive issue?
Is this season secretly building to an extended hearing on the multiple violations committed by the Cerritos crew over the course of ten episodes?
I heard Trek Central suggest this, but I'm not so sure.
If we're looking at a Prime Directive violation, we're looking at the interference with the social development part, or on a more granular level, interfering with the internal affairs of a civilization.
Sure, Bragh was a high ranking Klingon being part of the Oversight Council, but the death of Bragh was between Ma'ah and Bragh. Boims and Mariner participated in the Rite of J'ethurgh, but that wasn't interfering in Klingon affairs, no more than Picard participating as Worf's cha'DIch was. Technically, Ma'ah accepted them as part of his quv beq, so they were invited in.
And at the end, as far as Boims and Mariner is concerned, the Rite was over and completed - Bragh being a sore loser and the subsequent fight had nothing to do with them and they didn't participate in it - only witnessed it. Nor was the fight a foreseeable consequence of Mariner trying to get Ma'ah reinstated so she could get a Klingon Captain to assist in her mission, and especially not Bragh's death, which was only because he literally stabbed Ma'ah in the back after yielding (by granting Ma'ah his captaincy back).
So I really don't see the problem here. At worst they were bystanders to the death.
Ma’ah’s brother says all the “I can see the original Kahless” stuff at the end of the episode. That means that Kahless II being a clone is common knowledge. I wonder when that happened, though Kor seemed aware of it in DS9:”The Sword of Kahless”.
Worf insists that the truth about the cloned Kahless be revealed to the people at the end of "Rightful Heir", so I assume that info was part of the press release when Kahless was crowned.
I've always liked the idea that the Klingons are passionate enough about Kahless' promise to return that they're completely satisfied that the clone fulfils the prophecy.
Who actually was Bargh? He's the "leader of the Klingon Oversight Council," who are supposedly tasked with approving the eligibility of officers. That doesn't sound like a body which would actually command ships or fleets directly, but Ma'ah describes his ship as being part of Bargh's fleet. Bargh's death is also not presented as something that would significantly shake the Klingon government. Kor had been on this council (and rejected Martok) in 2345, but Kor would have been approaching 100 at that point and likely wasn't especially active in day-to-day military command.
So is Bargh essentially a minor administrator on a power trip, or a person of significant status and power who commands fleets but also has a role on this relatively minor council? My inclination is the former, and Ma'ah is expressing some sour grapes in referring to "his" fleet, but it's not clear.