Bodysuit and is the shortsleeve, legless things, with poppers by the nappy it is a vest for underneath everything else.
Sleep suit/baby gro have long sleeves, poppers up the front and enclose the leg and foot.
Cardigan for over the top if cold, then pramsuit if outside/blankets.
They wear an extra layer to you, so if your wearing a t shirt then they wear bodysuit + sleepsuit.
There hands and feet are always cold so you check their temp by feeling their back and chest for accuracy.
Don't bother with scratch mitts or booties, they fall off!
You will need a few hats too.
I have three sleepsuits in 'Early baby' up to 7.8lbs and three newborn up 11lbs in my bag. 0-3 will be huuge! Don't buy much as there will be lots of gifts.
The most I would buy is 6 of each type! I do have 0-3 but don't expect to use it for a couple of months. If you think logically there is not much chance you will have a 11lber at birth so newborn would be fine!