In terms of needs, slings, reusable nappies, cloth wipes... They don't make the cut because of the investment. You might invest and love it but you need the baby here and to test run this stuff. In terms of prepping with as little waste (both in terms of money and items you'll just not use) as possible, when the baby is here/a few weeks old, you can hire:
Various slings
Cloth nappies
Cloth wet wipes
You can rest run all the different brands and styles and work out what works for you.
Going out any buying 15 little Lambs or whatever might work out, but is likely to end up with you taking a loss reselling online when you realise they don't work well with your LO or you prefer the all in ones or whatever.
There are a million and one suggestions for what parents can and should buy, but a pack of disposible nappies for a few quid from aldi to make do before you can hire a cloth nappy kit is going to make your life easier.
Also, cotton wool balls stick to shit, cotton wool pads - the large ones - don't. Always get the large pads!