We don't really know what Biden will do about Nicaragua and Venezuela. About the latter, he, Nancy Pelosi and other mainstream Democrats appeared initially to follow the Trump/Bolton regime change fantasy of Juan Guaido. (Fareed Zakaria was a cheer leader as well, to his great discredit.)
However Biden subsequently adopted a more nuanced position, stating in his Americas Society interview, "The United States should not be in the business of regime change. Nicolás Maduro is a dictator, plain and simple, but the overriding goal in Venezuela must be to press for a democratic outcome through free and fair elections, and to help the Venezuelan people rebuild their country." https://cubapeopletopeople.blogspot.com/2020/08/joe-biden-and-kamala-harris-on-cuba.html
In principle that frees the Biden Administration from going through a US created leader and allows it to seek a political solution directly with Maduro and the actual Venezuelan government. The US can support rather than sabotage the Norwegian peace initiative or create its own comprehensive approach to the region that includes an end to all economic sanctions and embargoes.
I was surprised by your simplistic analysis of Cuba:
"The Castro’s outright rejected Obama’s policy of opening more doors to Cuba. The Cuban government opposed the increased US travel, people-to-people exchanges and free flow of remittances to individuals and private businesses. They treated it as a 'trojan horse' plan to subvert their rule. Their reaction was greater repression of dissenters and independent journalists and a slow-down in their own economic reform plan."
While Fidel, or old guard intermediaries around him, did criticize Obama, it is not hard to understand why. The embargo is used as an excuse but it is also a classic act of very damaging economic warfare. I think that Obama and now Biden are moving toward an end of the embargo--and the return of Guantanamo. Their step by step approach is understandable in the context of US politics but makes it hard for older conservative sectors of the Party to stomach being lectured to about human rights and free enterprise by the same government that has had a knee on their neck for sixty years.
However, over more than two decades of deep involvement with Cuba, I have never encountered opposition to, "increased US travel, people-to-people exchanges and free flow of remittances to individuals and private businesses" before or after Obama and Raul Castro normalized diplomatic relations. To the contrary.
Did state institutions try initially to maintain monopoly control, sure, but that seemed bureaucratically and economically driven to maintain institutional primacy and fund the state budget. There was steady growth of openness to the important role of the non-state sector, most obvious in practical cooperation with bed and breakfasts and private restaurants. That will go further in the new round of economic reform discussions if travel is a sector authorized for small and medium enterprise.
The "greater repression of dissenters and independent journalists and a slow-down in their own economic reform plan" did not come during the Obama Administration. It was a reaction to overt hostility and growing sanctions from Trump.
The US responded to perceived threat in World War II by mass detention of Japanese Americans. We responded to post war conflict with the Soviet Union by McCarthyite purges from government and educational institutions, by imprisonment and firings of members of the US Communist Party because of suspected disloyalty, as well as by mob action against left cultural events. Are you surprised that a country of 11 million responds harshly and defensively to an existential threat from a thirty times larger geographically and culturally close superpower and mistreats citizens who overtly support US aggression against national sovereignty?
Just as I believe Cuba would dramatically improve its economic situation if it adapted and adopted Vietnam's market model, I believe the US would dramatically strengthen its influence in Cuba if it followed the same policy of mutual respect and non-interference that it has with Vietnam. Do I hope that Cuba, like Vietnam, finds a path to a more liberal and tolerant multi-party political system? Yes, but the only role that US can play in either country's process is to give it space for its people to find their own path for their own reasons.
You can find my no doubt overoptimistic assessment of where Biden might go on Cuba as published by the Quincy Institute at https://tinyurl.com/CubaQuincy
I agree that Fidel's statement was negative. It was impossible for anyone to directly contradict him but my impression is that his words represented only the most cautious perspective within the government and Party.
It might have been impossible in terms of US politics, but I wonder whether Obama making a courtesy call on Fidel as the Pope did would have affected the atmosphere after his departure.
There was certainly not a negative change in policy or behavior about "US travel, people-to-people exchanges and free flow of remittances to individuals and private businesses". The atmosphere was increasingly positive.
The problem for evaluating whether repression increased is that the people complaining were against Obama's policy of normalization and could have been seeking ways to discredit it.
Did anything negative happen to the people who spoke frankly during Obama's session promoting private business?
Again, my memory is that serious backsliding was associated with Trump's election.
Because the legal conditions were different, Clinton was able to lift the embargo of Vietnam before he reestablished diplomatic relations. There were still conflicts after normalization but one of the biggest obstacles to establishing trust had been removed