Translation:Do you know what the crown princess of Sweden is called?
Ja, hun heter Victoria. Vi har ingen kunglig familj i Finland, så våra tidningar måste skriva om den svenska kungliga familjen.
Yes, "hon" of course. I've been doing Danish here and keep writing "hun" and "er". :P
This is slightly off the topic of language, but....
Is a "crown prince" or "crown princess" a royal child?
Does a "crown princess" become a "princess" at a certain age?
Or is the "crown prince" the one who is in line for the throne, and his brothers are just called "prince"?
Sorry if this is obvious but we don't have these people in my country and I'm not sure what the difference is between a prince/ss and a crown prince/ss.
Your last guess is correct - a crown prince/ss is the next in line for the throne and their brothers and/or sisters would just be called a prince/ss.
Because your phrase doesn't mention it is the Swedish crown princess that it's about.
In English, this word order is wrong.
If you start with, "Do you know what....," then the word "is" has to go to the end of the sentence, like this:
"Do you know what the name of the crown princess of Sweden is?"
Now it is grammatically correct.
However, the "what" and the "is" are not necessary. As a native English speaker, I would not put all of those words in the sentence. I would say it like this:
"Do you know the name of the crown princess of Sweden?"