1. It’s said that the hotel has been haunted for decades. If use present perfect, we put a certain time adverbial to emphasize the truth, which is “been haunted for decades” in this case. 2. It was said that the hotel was haunted. In this case, it refers to what people used to say. *In 1. and 2., they both make sense whichever we use while they are slightly different. 3. It’s said that the hotel used to be haunted. When we use “used to”, it’s implied that the house is not haunted now. When we use “it was said......”, it implies people talked about it before, but they don’t anymore. “It is said that to....” is an incorrect structure. It doesn’t exist.