The short answer is everything you can carry.
The newborn seems to need a lot of stuff. Obviously you need food supplies and bottles. This includes cleaning supplies, and warming supplies. Then you need diapers and wipes. Lots of "onesies", as they will get very messy, very quickly. Climate will dictate wether you need warm clothes and/or hats. Zip lock bags are your friends. Meds?. Good luck.