Those stereotypical long Hispanic names that we often see in movies are because of the naming conventions are so very different in Spanish speaking (and also Portuguese countries).

This of course goes back to one of your points about family having the same name, in those countries kids usually have different last names than both their parents.

Most kids in Spanish speaking countries will have two last names [Father's First Last Name] [Mother's First Last Name]. This of course has the effect that it's the two names from the grandfathers that are handed down by generation.

It's also not uncommon for children to have both names handed down [Fathers Two Last Names] [Mothers Two Last Names]. Meaning some kids have four last names at birth. When a woman gets married, sometimes they'll add their husband's names, meaning some women will have 6 last names (this is uncommon, but not unheard of).

Of course for social events you won't use all 2 or 4 (or 6). Usually just your first surname. The surname would be from your paternal grandfather - so what would normally have been your family name in Anglo countries. This is also the last name that athletes will use on the jersey's for example.

In Brazil it's similar, but the order is reversed. [Mother's paternal name] [Father's paternal name]. And athletes tend to go by their first name, instead of a last name. So footballer Neymar's full name is Neymar daSilva(surname from mother) Santos(name from father) Junior (because his father was also Neymar Santos). It is however rare in Spanish speaking/Portuguese speaking countries to actually use hyphens however. For this reason many Americans I knew have mistaken the names for being middles names when they see them written, rather than surnames.

In France the law has actually been that people have to use the names on their birth certificates. Similar as in Quebec. This means that while socially women may use their husband's last name, legally their last name is usually their maiden one. If you want to change it you have to go through the complicated procedure that people that want to change their names for any other reason but marriage follow.

In Italy the law is that people keep their last names, but wife's may add their husband's name on the end. It's all very confusing and different lol.