Hello all, I have been lurking for a while!

My first bub is due in April and I have just purchased 24 Bumgenius Organic One Size AIOs. Will they actually fit a newborn? I didn't really want to purchase any more nappies, my hubby would freak! Can I use a cover on them if they arent snug enough? Will I need to purchase some boosters/doublers for night time even tho they are an AIO? Will I need a cover or soaker for night time? And lastly should I bother with flushable liners for the first poos? Or would it be safe to think they will wash up fine?

Aargh! I have so much to learn.
Thanks