"the Cuban Govt doesn't stamp your passport for that reason"
The Cuban government don't stamp your passport because they don't have any stamps!
Having been a few times and having data on lens usage for my trip last year, I'd definitely want a lens longer than 28mm. In fact I'd want a lens longer than 50mm as well. No chance of persuading you that a wide-mid telephoto zoom is the best tool for Cuba?
hmm, really? What did you use a tele for? Tele personally isn't my style, though I would bring one to try it out if I owned one!