Either the use of the word kinbote was calculated by VN as I believe or as you put it he "could not foresee the significance that would be attached to his choice of the name ..."
Both are not possible in the world I live in. Either the choice of name is coincidental to the G = C = K = S solution or it is integral.
I don't think I have made a point of the fact that I had not read Jekyll and Hyde before I read Pale Fire. It was the solution (initially possible solution) that reminded me of VN's lecture on the RLS story, which memory caused me to read RLS's famous tale.
When I found the act of kinbote within the opening pages of Jekyll & Hyde it confirmed that I was, in fact had to be, on the right track.
I have explained above how I got to Jekyll & Hyde from Pale Fire - - how do you get to the Lord of the Rings from Pale Fire?