What happens if all the adults die and there are 3 children?

well you have tons of food so i would say they woukd survive with atleast a female so when they grow up they can reporduce

Avoid harvesting every last bit of your available honey, papaya, mango and banana. If you leave some on the tree, it recovers a bit faster. They won't starve immediately and your Chief may be able to supply magic food before they all croak.

TIP: Avoid increasing your population before your oldest child reaches working age. It keeps things in balance. If you get one of those really slow walkers, use her for your brood mare. Also, get a female chief. You don't need one until well into the game. She can be pregnant and still hold lectures. And advise when someone is sick. A female CHILD is the best, because as chief, she will still pick up all the stuff kids pick up and maybe end up being chief for 50 years.