Feel free to tell me which parts of the wheel I was busy re-inventing.
No problem

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A. Yes, this is the main line of analysis.
B. Yes.
C. This might be a novel variation I am not entirely sure. Still I am not looking too much into that variation. The idea that an admiral or the Sanctuary has enough engineering intel about the ETAK project is something that seems stretching to me. It might play a role, however the main catalyst for me is the urgency of the matter (given how the FEDs defeat is inevitable, a matter of time) and the silence of the Vishnans.
D. Of course, this and the consequences of this (for it is unclear for the parties what will happen in this moment to humanity) is a very big motivator for Steele and the morpheus contingency. A kind of "Childhood's End" scenario that could be either the creation of paradise or hell.
E (C?). This is somewhat speculative. Vishnans and Shivans span in multiple universes, while terrans are just some tens of billions of souls in ten or twenty systems. It seems a bit jarring and pretentious the idea that these "ants" would be a threat to any of these species, although the cliché is widely used out there. It is just "something about us humans", etc. What pretentious shenanigan, I have no desire to watch any of that garbage, and I think I can safely say the devs are also very watchful of that blunder.
F (E?). Consider that Ken is such a melded consciousness, consider that Al Dawa is such a consciousness. Clearly the Shivans also indulge in this consciousness melding technology, albeit seemingly to different ends. A minor (though interesting) variation of the possibilities hints at the Vishnans being a very very old
Shivan anima themselves that were created either for uplifting a previous living species (like the Brahmans, say), which could have had happened in the so-called "apocalypse" some billions of years ago, or alternatively they were "uplifted" into a summed psyche by the Shivans to solve the Great Darkness problem (again, possibly related to that apocalypse). Because that particular problem is so big, so became the Vishnans. Many possibilities here. The vishnans might have reached independence from the shivans (or were always so), they might be harvesting lower species to get more numbers for their SP, etc.,etc..
Last, welcome to HLPBB!