Online business could be the best option of you are taking care of 2 kids at the same time. We too have been thinking of what kind of business to put up since we also look after 2 children. We have finally decided that online business is the best option as we don't need to go out anymore and we can manage our time well. You just have to know who your target market is and what kind of product or service will best suit your target market. If you have a place nearby or within the same building or compound, it might also be convenient for you to set up a business.
It will depend on what merchandise you are planning to sell. If you are choosing between selling in the city or not, research what items would sell in the area, the demand and price range and if it is something that can be maintained. You must also research on how much items your starting would be, and your availability either online or physically while taking care of your kids and managing the business. If you plan to do shipping too, check which couriers are accessible in your area and which is the cheapest.
I think it's better if you establish your business near where you reside. That way you can properly monitor your own biz and you can gauge how things goes. Whether Manila or in the province, I think it doesn't matter. What matters is the volume of people as these people can become potential customers