The correct translation offered for this sentence is at times rather unnatural. Had to try three different combinations of responses to get the exact phrasing the translation was looking for, while each of my responses were sound English translations that achieved the same meaning. Hopefully newer translations will be included.
I'd agree that it's strange in English; maybe it's the standard phrasing in Czech, though. But other EN alternatives can be added if the CZ natives on the team feel that something like "What street is their house on" -- which might be the most-used phrasing in English -- is not too far away from the original.
“On which street is their house?” Or “Which (or what) street is their house on?” is far more natural in English. I have reported it. “On which/what street do they have their business?” would be appropriate, or “On which/what street are they having their party?” would be fine. The translation given is grammatically correct, but (in my opinion-native Am English speaker) would be rarely, if ever, used.
That is quite possible, but at the same time is a different Czech sentence "Ve které ulici je jejich dům?". Sometimes we really have to use a less common English sentence, but stay within the limits of English grammar, to better show what does the Czech sentence mean. If we deviate too much, other people report that we don't have the same words...
So which sentence in Czech would be more commonly used to simply ask on which street their house is located — Ve které ulici mají svůj dům? or Ve které ulici je jejich dům? Often languages don’t translate well word for word... for example, I would never translate “Jak se máte” as “How do you have yourself”. It would simply be “How are you?”