The only relationship the Cuban Blues has to American Blues is the same relationship they both have to the Universal World Blues.
This music is about as "authentic" as any music can get; Cubans didn't have to reach back to Africa because it came to Cuba and never left; while slavery beat the Africa out of the Africans. I know you remember "Roots" and Kunta Kente. "My name is Kunta Kente!" Yo name is "Toby" now! Well, anybody who saw "Roots" know's how that argument got settled.
I'll have to listen to a lot more of this music, and get back to you Frogman.