It's a minor difference because of the word order, but the difference between "Whose castle is that?" and "Whose is that castle?" would stress the importance of "Whose" in the first case, and "that castle" in the second. Of course, if you were to utilize stress/intonation on any particular word in either case you could reverse the meaning easily, but without that element this is a good way to translate it.
That sounds weird to me but maybe a native speaker can tell us their opinion...?
Several native speakers did answer that for us in agreement with you. Whose is the/that... is a highly suspect English formulation that typically marks its users as foreigners. We will probably accept it where the original is as Vala indicated, to survive beta testing. Welcome to the team!
When you play the audio from "cí" (don't have that letter c) it says a whole sentence, what does it mean?