As this is DC3 I'm not too clueless about what to buy. I buy the smaller sizes- DS was 8lb and DD was 7lb 10 and 0-3 would have been far too big! The first few weeks they were in first size/newborn.
Plenty of vests- personally I buy the short sleeved, I find the long sleeved ones get bunched up under the sleep suit sleeves!
Sleep suits and rompers- I mostly wear sleepsuits however did have a nice few all in one rompers for them to wear if they were going out for the day! Had jeans/dresses etc but rarely used them as they were awkward and uncomfy!
Plenty of bibs! I'm one of those weirdos who has never used a Muslin even after 2 children but I go throw endless bibs! Love the tommee tippee milk feeding bibs- they are padded up round the neck to stop milk dripping down.
Few little pairs of socks- it's hard to find socks small enough for a newborns skinny ankles! In the cold winter i put socks under sleepsuits to keep their feet warm. I remember getting nice small ones from GAP.
Little cardigans to wear around the house on top of sleepsuits. I love hand knitted ones.
Will need a snowsuit for baby for being out in the pram. both my others were summer babies so never needed one so early. I'll also get a little fluffy coat and some little knitted hats.
I've never used scratch mitts either- bought them both times but they are probably still knocking around the house somewhere with the tags on!!