I could believe a CT halfway between this and what Mallard was proposing. Perhaps Oswald acted alone and was not part of a conspiracy but thought that he was.
The scene is a Mexican bar. Oswald over hears a couple of drunk Cuban Consoles ragging on JFK. He walks over to their table and offers to kill Kennedy in exchange for 1 millions dollars and Asylum in Havana. One of the Cubans rolls his eyes and mumbles “Yeah sure dude knock yourself out” and then blots the entire episode from his memory with a fresh bottle of tequila. While Oswald confidently carries out his secret mission on behalf of Castro.
No evidence that this happened but it could have and that’s the important thing.