Make the mango: Combine the coconut milk, mango and salt in a small saucepan with 1/4 cup water; bring to a simmer over high heat. Reduce the heat and simmer until the mango is soft but not falling apart, 20 minutes. Let cool, cover and refrigerate until well chilled, but no more than 2 hours.
Make the tea: Combine the coconut water, lemongrass, lime leaves and chile in a small saucepan; bring to a boil over high heat. Turn off the heat, cover the pan and let the mixture steep for 20 minutes. Strain, pressing, then discarding the solids. Stir in the condensed milk until smooth. Cover and refrigerate until well chilled, but no more than 2 hours.
Make the halo-halo: Right before you're ready to eat, layer the ice, mango mixture, tapioca, macapuno, nata de coco, fresh fruit and cereal in 4 bowls or tall wide glasses. Pour the milky lemongrass tea over each.