Those are all pretty good points.
But I remember my mom telling me that a lot of Puerto Ricans were often very anti-communist, because they feared Castro invading the island. Many Latin Americans developed a good hatred of Castro.
Wouldn't the obvious success of a pro-Western Cuba, and the obvious failure of Che Guevara's Cuba scare a lot of Latin Americans away from communism?
How obvious is West Cuba's failure though? I assume they have the propaganda meter pumped up to eleven.
Also, anti-Americanism in Latin America is a really potent historical force. A lot of people will consider either outright aligning with the Soviets, or at a minimum, trying to use them to balance the U.S.
That said, Brazil's going to go badly for the Soviets and their clients fast, since
@The Congressman is already talking about the communists pushing out their allies, and a lot of the terrain, plus the underlying social and racial tensions that an upper class vanguard of the proletariat type communist government might exacerbate will make any kind of counter-insurgency campaign there hellish on the reds. Brazil could be TTL's Afghanistan moment for the Soviets.
One interesting note: this is around the time Pentecostalism starts to make serious in-roads in Brazil, so you could see a pretty explicitly Christian--Pentecostal plus conservative Catholic--resistance movement.
On the other hand, Argentina's more likely to get into, and lose, a pissing contest over the Falklands that will weaken the new communist-aligned government; kind of a reverse situation of what brought down the junta OTL.
Will a certain Jesuit priest named Bergoglio find himself in hot water with the Argentine communists by any chance?