Packing Q: how do you pack for travel from a cold climate to a warm one?

In December, my husband, myself, our 5 year old and our 9 month old are traveling from NYC to Hawaii for two weeks.

We did this last year and went to CA, but it was actually a little cold, so we used the sweaters and coats that we brought from New York. That said, we didn’t have the baby and our bags were HEAVY.

We’ve also been to Hawaii in December before, but our oldest was 18 months and didn’t wear diapers.

I’m hoping we can wear: packable jackets on the plane, bring 1-2 hoodies each, 4 short sleeve shirts, 2 shorts, 1 pants (1 to wear on plane) and 1-2 pairs of shoes.

For the baby, I was going to pack 20-30 diapers since we have layovers, but buy a box when we landed.

Baby is breastfed and will be eating solids by the time of our trip in December, so I was going to bring 1-2 bottles for pumped milk and a manual breast pump.

We fly from NYC to ATL to HNL, spend a few days in HNL and then we have an inter island flight to Kauai. We spend a week in Kauai and then we go back to HNL and then ATL and NYC (an overnight flight).

Any experts on here have tips on how to travel light with a toddler and infant between climates?

Any other tips that I am missing?