WN nappy fastenings are all popper. Their own inserts are currently being redesigned, so are unavailable. but i use microfibre on top of hemp quite successfully during the day. We don't use pockets overnight, so can't help there - sorry. As to design, it really is up to you (and your budget!). We have velboa, minkee and cuddlesoft fabric nappies from WN. Oh, and some double fabric ones, too (a combination of minkee and cotton in a bordre cut combo).
This may well sound like I;m talking double dutch.
The best thing is to explore the WN website for ideas. Or look on here to see if you can pick something up second hand.
excuse typos: nak.