Ms.Liza,
Madame Tussauds Museum is not on Lantau Island. If you plan to visit it from Disneyland, you need take Disneyland Resort Line to Sunny Bay, change Tung Chung Line to Hong Kong MTR Station, walk to Central MTR Station, get out at Exit J2 and walk to Central Peak Tram Terminus. Then take peak tram to the Victoria Peak. Madame Tussauds Wax Museum is located in Peak Tower. Remember that the wax museum closes at 22:00.

Ngong Ping 360 and Giant Buddha are two must-sees on Lantau Island. You may take Disneyland Resort Line to Sunny Bay and change Tung Chung Line to Tung Chung MTR Station. Then walk to Tung Chung Cable Car Terminal to take Ngong Ping 360 Cable Car to Ngong Ping. There you can walk around 5 minutes to Giant Buddha.