Your requirements can't be ...

Your requirements can't be readily met in a tropical environment.  If you don't want to get sick, you will need disinfection, which requires either chemicals (HYPOCHLORITE) or energy (UV).  You could restrict the disinfection to the drinking water only.

Bacterial and algal growth will be your greatest problems, along with the nutrients from the atmosphere in rain water.  I survived for 18 years on a farm with untreated rain water, but it was in New Zealand and we were far from a nutrient rich atmosphere.  It just rained a lot!

Whatever you do, you will need to exclude light from storages.  To reduce nutrients, a first flush system will help.

Grey water can be used for irrigation.  

Good Luck