All of what you wrote in Japanese are a correct and natural way. It just about interactive problems. 日本はうつくしい→ it a like general truth. Japan is the beautiful country. but if you say 日本がうつくしい, the sentence must have specific detail about what do you think or feel beautiful about Japan. ex. アニメは日本がいちばん。in English → Japanese Animation is the top of the world. 「たなかはかみがみじかい」means that Mr. Tanaka is a man who has short hair but「たなかのかみはみじかい」refers to the specific point or truth which is Mr. Tanaka's hair is short.

日本がうつくしい

たなかのかみがみじかい