Newborn baby shopping list...?

Babies spit up, poop, and get stuff dirty really fast. It is not uncommon to go through 2-3 outfits in a day, so it depends on how often you want to wash clothes. I would have more clothing than that. Yes, the babies will be fine sleeping in a onesie if it is very warm. Ask your pediatrician about temperatures if you are not sure. You will need some bottles (you mention a breast pump so I am assuming you will express to feed them). It is really handy to have some type of swing or bouncy, especially with twins because you can't hold them both all the time. Keep in mind you can get things second hand so no need to go buy everything new. Check on Craigslist or look at a consignment or resale shop near you. Good luck.