TeniBear, I found we needed only one Snappi, as you just take it off the old nappy and put it on the new one - so I also knew where it was! Only problem is if you take off a clothie and put on a sposie and don't have a place where the Snappi lives so you can find it again. So maybe one for the change table and one for the nappy bag, then you're not trying to remember where you left it...

I know what you mean with the covers, it's a bit confusing! I found that I could use 'small' sized Bummis, Thirsties and Motherease Rikki from birth (she was 3.27kg = 7.2 pounds) and she's only just growing out of them now, 6 months later, which is pretty good. I wouldn't bother with getting wool for a NB as they poo so often and it's liquid and leaks really easily, so you have to wash the covers much more often than with an older baby. I have no experience with fleece covers, I just got PUL; I think they are often cheaper? New Age Nappies and Baby Beehinds both have sales on at the moment, maybe check them out.
Good luck!