Thanks! Good questions!
Mary Anastasia O'Grady said on Fox Business around Feb 19 that Raul Castro told Maduro that if he tries to run the Cubans will kill him. Maduro is probably a prisoner of his elite Cuban bodyguards.
The Cubans want to hold on in Venezuela, perhaps of getting more oil for themselves. Cuban income is sketchy.
O'Grady also said that for many years Hezbollah has been on Venezuela and other Latin countries. They hold Venezuelan passports.
We know, for example, that Argentina has had connections to Muslim terrorists since the two Iranian terror attacks against Argentine Jews in Buenos Aires in the 1990s. Remember Juan Peron was a fascist/socialist and Peronists have dominated Argentina since the days of Mussolini. Many people on Argentina are Italian as is the Pope and the Italians in Argentina have been the dominant fascists. Peron was Italian. So Latin America is a hot mess of fascism, communism, socialism, drug trafficking, sex tourism, Islamic pyschopathic jihadis, arms dealing, and Russian, Chinese, North Korean, and Iranian influence.
The Russians are sending in troops and supplies. My guess is that they might be sending in engineers to restart the oil wells that Maduro ran into the ground by replacing engineers with communist party hacks.
The Russians are losing a lot of money in Cuba. They recently forgave a 30 billion dollar loan that the Cubans would never have repaid. Now all this money in Venezuela is coming out of Russian pockets.