Re: how does this sound?
I'd do newborn prefolds and newborn covers. When your baby outgrows the newborn covers, you can trifold the prefolds in OS covers (shared with your toddler).
Then for your toddler I'd do flip organics and flip covers (shared with the baby).
So I would buy,
24 newborn prefolds (you will have to wash every 1.5 days, 2.5 dozen or 3 dozen would be nicer...)
18 flip organics
12 flip covers