Hi there,
It's my understanding that Cuba would have been very insignificant in terms of the NSDAP AO. There was certrainly no Adolf Hitler Schule (AHS) in the sense of AHS Heiligendamm, AHS Tilsit etc but I guess that there may have been a primary school called "Adolf Hitler Schule" as indeed there were in Germany i.e. schools that were not part of the AHS system but which simply called themselves "Adolf Hitler Schule" to show their support. Cuba took Jews in who were escaping nazi repression and who wanted to use Cuba as a springboard for a later move to the US so I wouldn't say that the country was a nazi stronghold by any means.