Baby Shopping 😍

Em
I'm currently in the process of buying clothes and can't decide on the sizing or the amount of clothes needed 🤔
Will 0-3 months be too big if newborn is small in size? I mean it will be winter so will probably be wrapped in swaddling blankets but still please help me out..
Will a newborn be more comfortable in vests and leggings (due to the healing umbilical cord)? 
Bodysuits (is it worth getting the long sleeve ones? I was thinking about buying sleeveless and just layering a cardigan on top)