Whole house RO filtration is going to be costly. There is nothing like it if you can afford it. You can drink out of any tap and because RO water has very less minerals, chrome bathroom fittings will always remain looking like new. Also it will do wonders for your hair
You will need a lot of pre-filters to filter out the ground water, before it reaches the RO membrane. Starting with stainless steel mesh filters, followed by polypropylene filters. Without the pre-filtration, you will kill the RO membrane pretty soon and it is expensive to replace. Pre-filters will need to be replaced frequently, maybe once a week depending on your water usage.
Post and pre RO carbon filters and remineralization filters are only required if you want drinking water, for general use you don't need any of those.
I have a domestic RO unit at home and I don't use a remineralization cartridge. Although you are right that RO does remove minerals, there is no study that says RO water is bad for health because it contains very less minerals. Everything we eat has minerals in it so rest assured that drinking RO water will not cause a mineral deficiency. But if it gives you peace of mind, then there's no harm in having a remineralization cartridge. It doesn't cost that much anyway. But it won't add many minerals anyway, not in the quantity that are removed by the RO.
I know someone who imports complete RO units for domestic and industrial use from Taiwan and China. He is the main distributor for Multiply RO (Taiwan) in Pakistan. You can get the unit from him on wholesale rates. If you're interested, let me know, I'll PM you his contact details.