Our LO has a decent sized belly...but skinny little legs! We have been having pee leaking issues with our Ecobumz, coming right out the leg, as well as the Little Joeys, and I'm worried that our FB Smalls are not quite tight enough around the leg either. She's currently in a Thirsties Duo cover with prefold, so we will see how that goes; I think the double gusset will help.
Would love recs on a good diaper for babies that don't have those adorable chunky thighs! Bonus points for a diaper that is DH/baby-sitter/nanny easy :-).
Re: Diaper for skinny legs
Newborns seem to all have skinny legs til they hit 3 months or so, but even then my son stayed on the skinny side (he's been around 12% for weight since some of his very early check ups). Thirsties covers seem to be tightest around the legs; BumGenius AIOs are also somewhat tight on the legs. FB might work, but you will have to wait a while. They didn't fit well until he was over 13 lb (same for DD). He wore the size small from 3-13 months. DD might have thicker thighs than DS, but for the most part diapering is going the same for her as it did for him in the early months.
You can probably avoid HH because they seem made more for thick thighs. FB one-size was a joke for us as well. We had leaks from the legs almost every single time he wore one.
Until you get through the newborn phase, you will probably do best with something inside a Thirsties cover or with BG AIOs. We really like the Thirsties Fab Fitteds, but you can't buy them anymore. I have not tried the Duo Fab Fitted. Prefolds are always a good choice, though you may have leaks INSIDE the cover from time to time. They still shouldn't escape the cover very often, if ever.
HTH!