omfg spoiler tagz
For one thing, Ken certainly does not sound like Aken Bosch in the crate-messages during Noemi's vision. The use of "we" in the message, particularly the "we too fight our own war in heaven" sounds very much like a shivan talking as he/she/it would be more likely to refer to he/she/it's race using "we" and "our", whereas if it was a 1 to 1 conversation with Bosch playing the role of Ken I'd expect to see "I too fight my own war in heaven", assuming he's assisting the shivans.
If Bosch has been influenced by the Shivans, or is otherwise working with them, it's perfectly conceivable that he would refer to Shivans as "we".
Additionally, the Ken = Bosch theory runs into difficulty just due to the timeline. Specifically, how the hell do the shivan's know to specifically groom Noemi to work as their agent immediately following Capella? Either they:
A: Can view time-space in bulk vishnan style, which doesn't seem likely given the very large amount of differences in how the vishnan's and shivans fight AND the "we shall see about that" comment at the end of AoA, which certainly doesn't sound like somebody who already knows the result.
Their time could exist orthogonally to ours. Imagine looking at a stream: if you toss in a stone so it blocks the stream, the flow is affected downstream. Time is essentially flowing in the stream's direction. A statement of time for them would have little meaning to us, since their time is an entirely different concept that we probably cannot even observe, but it would be meaningful for them. And maybe their plans involve the Terrans and Zods of the near future, making their future our future for this one specific conflict.
I'm just saying that could be another possibility.
B: Have incredibly detailed intelligence on both the UEF and GTVA, detailed enough to correctly predict every major economic/political event that leads to the civil war.
Given that they can observe the entirety of our spacetime, that doesn't seem unreasonable.
C: There is a incredibly convoluted explanation including the multi-verse (I doubt that was thrown in there for ****s and giggles), whatever the Sathanas fleet was trying to do when they blew up the Capella star, and time-travel, with the end result being something that is only going to cause headaches trying to figure out.
Well, interdimensional travel does seem to be a major point so far, at least symbolically. Remember that the Shivans (presumably) entered a new dimension while destroying the Capella star. The Vishnans allowed us to return to our spacetime (and probably yanked us out of it in the first place) by changing, while preserving an existing node. We, inadvertently, crossed barriers while recreating a node back to Sol- albeit with Vishnan help, and certainly not intentionally.
But to bring it back to Bosch, options A and C involve shivan-specific characteristics, and B is just plain unlikely as hell and frankly a bad explanation to begin with.
The point I'm trying to strain out here is that while the Ken=Bosch theory is interesting there's no way to tell if Ken is Bosch or a Shivan. I'd put very good money however on Ken NOT being a vishnan though, my primary argument stemming from the fact that Vishnan's refer to the shivan's as their sisters, whereas ken refers to the other side of his war as brothers. So either Ken is NOT a vishnan or there is a 4th race we know absolutely nothing about that somehow got involved while we weren't looking.
Going by the species we know so far, Shivan is the most likely choice for Ken. Some of Ken's lines mirror Aken's, and the message he presents is virtually the same as Bosch's reasoning for the NTF.