For auto-composting (not sure how micro you need to go...), we're thinking of using Black Soldier Fly Larvae to process the compost and auto-harvest into the fish tank for a snack for the fish. Another option is using earthworms, and manually (eventually automatically) harvesting them into the fish tanks, thus recycling one's food scraps back into food.

As far as blight and mold, those problems have been identified and solved with greenhouse and hydroponics growing. The key to these problems and other diseases is to make it easy to prevent, or failing that, treat those diseases. But again, this is a solved problem.