1. P.S. to Mosiah 9. There's an interesting ambiguity to the two accounts of Zeniff's revolt, in Omni and in Mosiah. I think the normal way to read them is that Omni's "stiffnecked man" and Mosiah's "austere and bloodthirsty" "ruler" are the same unnamed man, Zeniff's commanding officer. But this guy isn't identified, and I think there's another way to read these verses: that for Omni, the "stiffnecked" leader is Zeniff, and for Mosiah (Zeniff), the "austere and bloodthirsty" "ruler" is Benjamin. This gives us more nuanced visions of both Zeniff and Benjamin, and eliminates the need for an unnamed mystery officer in our interpretation, and explains why Omni doesn't have Benjamin comment on or try to help Zeniff's apparently righteous mission, and why Zeniff doesn't say anything about the apparently righteous King Benjamin.
It's an interpretation, a theory. I think the accounts can be read either way, and it's not clear to me that Occam's Razor cuts in either direction here. Personally, I kind of like to think of Benjamin as an amazing man who was not perfect. But that's me.
2. Mosiah 10 reminds me of 2 Nephi 5, in which Nephi talks about his people in the same place. Hard to imagine the similarities are accidental -- Zeniff sees himself as the new Nephi.