Yes Crypto Jews are the Sephardic (Spanish) Jews because of the inquisition. Many went underground or converted to save their lives. This not only happened in Spain but Italy too. Spanish and Italians are cousins. Their language is almost the same only pronounced differently. Even people who weren't Jewish that went against the Catholic church were persecuted during the inquisition.
Not only slaves were taken into the Islands but also Indians as slaves. I have a good friend who is Cuban. His mother is a Saintaria (sp) priestess. Most of the people from the islands are African, Indian and Spanish. Saintaria is a combo if all Saints, African Voo Doo and Indian practices.