The eggs should be ok at 83-85, but I would go a little higher; 86-88.
We haven't dealt with a lot of hatchling DIs, so we couldn't really say that they NEED to eat an adult's feces for the gut flora, but it wouldn't be a bad idea to offer it to your hatchlings for the first week or so. It would be best to keep the babies in a separate cage, and collect feces from the adult cage. We have seen babies and adults in close proximity in the wild, but you never know how they will act when housed together in a captive setting.

Good luck with the eggs.
Nick & Austin