Thank you, JDiver. Great information. ^
I assume a tour operator, such as Insight Cuba, who can take Americans to Cuba legally will help arrange for the health-insurance requirement to be met?
The "back door": Some Americans travel from Canada, Mexico, Bahamas, Costa Rica, etc. to / from Cuba.
Costa Rica is no longer a gateway to Cuba. Avianca (formerly Taca) has pretty much "dehubbed" SJO, so their itineraries to HAV from here now require a connection at SAL or BOG. And Cubana no longer flies here.