In small saucepan, combine gelatin and lemon juice; let stand 1 minute to soften. Add water; cook over medium heat until gelatin is dissolved, stirring constantly. Set aside to cool.
In blender container or food processor bowl with metal blade, combine melon, liqueur and honey; blend until smooth. Add cooled gelatin mixture; blend until mixed. Pour into shallow nonmetal freezer container; refrigerate about 10 minutes or until mixture is thick and syrupy, stirring occasionally.
Meanwhile, in medium bowl, combine whipped topping and yogurt; blend well. Fold in chilled melon mixture. Pour into same freezer container. Freeze 3 to 4 hours or until almost firm, stirring occasionally.
Place mixture in large bowl; beat with electric mixer until smooth and creamy. Freeze 2 to 3 hours or until firm.
To serve, let stand at room temperature for 10 minutes.