JC--
By some accounts, LHO in MC said he wanted to assassinate JFK.
The JFKA was likely plotted after it was announced JFK would visit Dallas, where by chance LHO resided.
The motorcade route was bad luck.
LHO and confederates took advantage of circumstance. The plot was very simple. Two or three guys with guns.
Fidel Castro ordered Cuban intel to monitor Dallas radio transmissions before the JFKA. He knew something was up.
Since nobody knew there was going to be a motorcade in Dallas, where it was going to be routed, and that it would be routed past a building that Oswald didn't even work at yet, why would anybody think any of Oswald's activities in Mexico City had any connection to the JFKA?