We had a similar problem with Rowan when she was tiny, skinny waist and chunky thighs and 63cms at her 6 week check. Diddy Diapers worked well for us but she did outgrow the size 1s by about 12 weeks so you wouldn't get a huge amount of wear out of them. They do a size 2 as well though. Weenotions Northern Lights were also good and as a two parter had great poo explosion protection!!
We used Bamboozles for a while but they were a similar fit to the LL so had problems with rise. Not sure about AIOs/AI2s as we didn't start using them or pockets until Rowan was about 9 months. I made do with Toby's old MEOS for a while after she outgrew all her first size nappies. Sorry, not much help there. Hope something soon.