You can serve the breakfast mango rice pudding warm or cold. If you want to make it in advance just cover the bowls with plastic wrap and keep in the fridge for up to 2 days.
If you feel that the liquid has soaked up during the cooking process and the rice isn’t cooked, add more water to get the consistency you like. Different brands of rice cook differently.
If you want to heat up the rice pudding in the morning, store the mango puree and the rice pudding in different containers. Pop the rice pudding in the microwave in the morning and add the mango puree later.
You can use canned mango but I would suggest to leave out the agave syrup in the puree if your can contains extra sugar.