Oscaroscar - the only info I could find on enviro nappies were all cotton nappies from the UK. For you the best absorbancy and trim ness look for fabrics such as bamboo, hemp and microfibre.

AIO (all in ones) are great for time and ease of use but keep in mind traditional AIO are all sewn in layers and can take longer to dry. AI2 (all in twos) or snap in AIO allow you to seperte the layers for drying (although some of my AI2 I leave snapped together in the wash :-)

OSFA vrs sized - We have really only used OSFA nappies for our cloth nappy journey - I just see more value in them and have rarely had a problem with fit but my DD gained weight fairly rapidly. If you can get a medium size (generally 5-11kg) you can get quite a bit of wear out of these.