When then Prince Henri married Maria Teresa, it was mentioned in the evening television news in New York City where I live. It was a mere few seconds, but it was nevertheless mentioned. Also, I believe that the New York Times, considered the most important paper in the USA, ran a photograph with some subtitles. Let me add that the focus was that it was a royal wedding. The fact that Maria Teresa was born in Cuba was incidental and was only mentioned in passing. The focus was that there was a royal wedding--period.
This was before the Internet, so most of the news for those of us interested in European royalty and nobility was gotten via European magazines like Spanish, "Hola," French "Point du Vue," "Paris Match," "Royals" and various German magazines that I, also, remember carried pictures of the young couple on a regular basis. By the way, while the Brits are mostly interested in their royalty to the exclusion of other countries, their famous magazine, "Majesty" has in the past covered the Luxembourgish royal family on quite a few occasions, so expect them to cover Guillaume's wedding, especially if another member of the British Royal Family attends.
The wedding will definitely stir much attention. Perhaps not so much in the USA or Britain, but definitely in neighboring Belgium, probably Holland [aren't the Luxembourg family, Orange-Nassau, making them close cousins of the Dutch Royal Family?] France, and definitely in Spain where the groom's mother Maria Teresa is well known, because she is of Spanish ancestry. The Spanish magazines are fond of always mentioning her Spanish roots. Years ago, Maria Teresa visited Sitges, Catalonia where her paternal father's ancestors hail from and "Hola" had a two page spread on it.
Regarding Maria Teresa's children, I think that they are thoroughly Luxembourgish. Yes, their mother is Cuban, but that doesn't mean anything. Don't forget that most European royalty is mixed with some other nationality, yet, they don't think of themselves as that other nationality. Example: Phillip, Prince consort of England, was born a Prince of Greece, yet, Charles doesn't think of himself as Greek in any way, he is thoroughly British, neither does Prince Felipe of Spain who's mother Sofia was, also, born a Princess of as Greece, think of himself as Greek in any way. He is thoroughly Spanish.
In any case, I am very excited about this wedding. I can't wait! Thank God for the Internet! Even if we don't see it live, someone will post it on Youtube and the Official Royall Court Website will undoubtedly post it on their website!