Just as an FYI, "Whose is the dress?" is not a proper English sentence. "Whose is it?" is the correct way to find out which person owns a particular item. "Whose dress is this?" is the correct way to find out which person owns a particular dress - when the item / dress is known from the context.
Also correct English would be to say, "The dress is whose?" rather than "Whose is the dress?" I used the former rather than the latter and was marked wrong. I have also used "Whose dress is this?" and was also marked as incorrect. I don't appreciate having to memorize the expected incorrect English translations of these exercises.
No, "the dress is whose" is not correct English. In English, the question word goes first in the sentence. So "Whose dress is it? is best. "Whose is the dress?" is an awkward but acceptable alternative. I don't like it being used as the primary translation. Best to begin with "whose dress" and follow with "is it/this/that/"