Fruit flies gut loaded with bee polen, powdered milk, and kelp powder. LIGHTLY dusted with calcium. That should keep them going while the real jackson owners chime in on husbandry and d3 schedule for babies.
Firstly, congratulations!! I only have expeience with my Xanth baby, but here are the main bits - Basking temps no higher than 80F, and higher humidity - around 75% upwards, with a drop in temps of at least 10 degrees at night. Screen cages are beneficial for these little babies as they need good airflow too with all that humidity so the air doesn't become stagnant. At this young age hydration is just as, if not more, important than feeding. Dehydrated chameleons don't eat very much. As far as supplements - the key is to gutload the food as well as you can rathr than rely on supplements. Jacksons can easily be over supplemented and it is much easier to correct under supplementation than oversupplementation as it builds up in their systems over time. I followed the following schedule with my baby Jackson Xanth and I still follow it today. Plain calcium 1x per week, Reptivite WITHOUT D3 1x per week and Retivite WITH D3 once evey 6 weeks.