Blend strawberries, sugar, lemon juice, and water until smooth. Pour into a shallow freezer container. Freeze at least 4 hours or overnight until solid.
Combine coconut milk, lemon juice, sugar, and vanilla. Whisk until sugar dissolves. Pour into a second freezer container. Freeze at least 4 hours or overnight until solid.
Blend blueberries, sugar, lemon juice, and water until smooth. Pour into a third freezer container. Freeze at least 4 hours or overnight until solid.
Remove strawberry layer from freezer. Break into chunks. Blend with ice cubes on high until smooth and pourable. Transfer to a jug. Return to freezer.
Rinse blender. Break coconut lemonade layer into chunks. Blend with ice cubes until smooth and pourable. Transfer to a jug. Return to freezer.
Rinse blender. Break blueberry layer into chunks. Blend with ice cubes until smooth and pourable. Transfer to a jug. Return to freezer.
Line up all eight cups. Work quickly from this point.
Pour strawberry red layer into each cup filling one third of the way up.
Pour coconut lemonade white layer slowly over the back of a long-handled spoon held above the red layer. Fill to two thirds.
Pour blueberry blue layer slowly over the back of a spoon above the white layer until cup is full.
Garnish immediately with strawberry slice on rim, blueberries on top, paper straw, lemon slice, and mint sprig.
Serve immediately.