CE 15 didn't appear until well AFTER the assassination, and by the time of the assassination, and I mean ASSASSINATION DAY, all plans to link the assassination to the Russians had been terminated. Oswald was to be the "lone" nut, as in: he wasn't involved with anybody in the killing of Kennedy: no other individual, no group; nobody; just him.
Furthermore, if the Russians had come to Oswald, that would have meant something. But, the story had it that Oswald went to the Russians- to get a visa. So, how does that put the Russians involved in killing JFK?
In other words, the plan you are talking about had been aborted by November 22, 1963. The purpose of the letter was to establish that Oswald had gone to Mexico City- which he didn't do. The letter starts by referencing the alleged trip to Mexico City, and most of the letter concerns it. There is absolutely nothing in the letter that could be construed to suggest a Russian link to the assassination.
There is absolutely nothing there to suggest there was a Communist plot to kill Kennedy. That was not the purpose of the letter. The letter is all about Oswald. The conspirators were NOT, at that point, trying to bring the Russians into it. They were not trying to frame the Russians for conspiring with Oswald to kill Kennedy.
Idiot Backes had the nerve to recommend that I listen to John Newman, who said this:
Now, why would I want to listen to an idiot like that who says such stupid things? The right "John" to listen to isn't John Newman, it's John Armstrong.
Here is John Armstrong talking about "The Mexico City Hoax" on Black Op Radio: