In my opinion, the usage of だ is already correct in the following sentence. But someone in my other questions said it is incorrect.
映画を見ることが好きだ女性は私の妹です。The woman who likes watching movies is my younger sister.
使い方が便利だ電気機は何ですか。 What is the electric appliance that is handy to use?
For the sake of completeness and comparison, I provide relative clauses with a verb, i-adjective and noun as follows. I think they are also correct.
a verb: 映画を見ている女性が誰ですか。Who is the woman watching a movie?
i-adjective: 物価が安い町に住みたいです。I want to live in a town whose living cost is cheap.
noun: ジェットさんが２０歳だ映画を見ています。I am watching a movie in which Mr. Jet was 20 years old.
Must I change every だ to な in the given examples above? Please correct me if it is wrong.