@AnxiousAnnie94 honestly, vests are absolutely fine for a baby to live in! DS basically lived in short sleeved bodysuits + long sleeved sleepsuits until he was about 8 months. It just made life so easy especially when dealing with poonamis. We’d sometimes supplement with slippers and/or light leggings / light trousers but when he was in the house he was usually just in a bodysuit and socks.
In terms of sizing - I was living overseas and there was quite a delay in getting anything from the U.K. (6-12 weeks at its worst) and local sizing was even more unreliable. So we just went for 0-3 months and it was fine. For sure 0-3 months seemed pretty baggy for a while but I don’t think he minded! He was 7lb when born so basically average. I agree with others that if you’re worried, get some newborn stuff too so you have the option. But we were happy with 0-3.
Layers are key with little babies. So get a selection of short sleeved and long sleeved bodysuits, tops / jumpers to go over the bodysuits, leggings and trousers and socks to go over the bodysuits. Sleepsuits can be supplemented with bodysuits underneath if you’re worried about the cold.
Consider what you’re going to take DC home from hospital in, clothing wise. We swaddled DS (yes, swaddled in the car seat, probably not best practice) and it was 25+ degrees. If it’s not so warm here, we’ll go for bodysuit, trousers, socks, jumper, maybe an additional top. I don’t think it’s worth buying coats and pram suits until you know the size of the baby as they’re relatively expensive items.