My only problem with this otherwise flawless look at Big Walder is that you repeat the word psychopath where you often mean sociopath, noted by a lack of emotion or feeling BW seems to feel towards a number of moments that should warrant a reaction, as well as his bluntness and lack of tact when stating things without regard to the mood of the room or nature of the incident. This by no means devalues your assessment, as you did initially use both words near the beginning in tandem. The only reason I bring this up - and hell, I'm only about halfway done, so I will be scrolling back up - is because it's halted my flow of reading.
Alright, back up I go. Curious to see if there's any new insights therein. Thus far, you've nailed it.
Edit: I want to add that while many sociopathic tendencies would be present in a psychopath, psychopathy is often underscored by abject violence, abnormal or otherwise, a seeming instability and aggression. None of these traits are particularly present in LW, with the exception of a thesis that might look to proving BW having killed LW, and even then, I'd still be weary of using that term.
Second edit: I laughed when I hit the BW killing LW portion, as I hadn't quite reached there when I made the first edit. It's a pretty good breakdown.
All in all, my only gripe was brought up by OtherFromAnotherMother, comparing speech and textual clues for who went on the hunt. I'm in the LW camp, as well. I made a post once comparing their ways of speech, and specific tendencies therein. Nothing you've stated went overlooked, but I simply can't draw the conclusion that it was BW on that hunt. The evidence simply isn't enough.
That said, I don't particularly think that sways the quality of the post. Further, your Machiavellian analysis of LW effectively getting the Freys and the Manderlys at each others' throats following the death of LW is deviously enjoyable. Even if it doesn't end up being true, I want it to be. It's amusing at the least, and it would be an excellent set of actions that complement his motivations, at best.
Ah, let's hope he continues to rise, that Big Walder.
Third Edit: Fixing my idiocy by calling one Walder by the other's adjective.
Fourth Edit: Still fixing my idiocy.