1. To prepare watermelon layer, combine 1/4 cup sugar and 1/4 cup water in a small saucepan over medium-high heat. Bring to a boil; cook 30 seconds, stirring until sugar dissolves. Stir in mint; cover and let stand 30 minutes. Strain through a sieve into a bowl.
2. Place watermelon in a blender; process until smooth. Strain puree through a sieve into bowl with mint syrup; press with back of a spoon to extract juice. Discard solids. Stir in lime juice; cover and chill 1 hour.
3. Pour about 2 1/2 tablespoons watermelon mixture into each of 8 ice pop molds. Freeze 1 1/2 hours or until almost set. Arrange 1 wooden stick into mixture, being careful not to push through to bottom of mold. Return to freezer. Freeze 1 hour or until frozen.
4. To prepare lemon layer, combine 6 tablespoons sugar and 1/2 cup water in a small saucepan over medium-high heat. Bring to a boil; cook 30 seconds, stirring until sugar dissolves. Pour into a bowl; stir in lemon juice, orange juice, and extract. Cool 15 minutes; cover and chill at least 1 hour.
5. Remove molds from freezer. Pour about 3 tablespoons lemon mixture over frozen watermelon mixture in each mold. Freeze 2 hours or until completely frozen.