My kids are at that age where they can't wear small adult sizes but they are out growing the largest youth sizes. Trying to find waders for them was a daunting task. I either found waders for toddlers or young adults but nothing for that sweet spot in the middle. I finally ran across BASSDASH IMMERSE Kids Breathable Chest Fishing Waders.
Finding boots was another interesting adventure. Luckily both my kids wear around a size 8 wms shoe and I found some boots at BassPro.
This wasn't the cheapest setup but it fit my criteria. I wanted waders that would fit properly and wouldn't be prone to filling with water if the kids fell in. I also wanted boots that wouldn't be slippery even in mud. Keeping the kids safe is my highest priority. I posted this in the hopes it will help anyone else in the same position looking for gear. My kids are just under 5ft and these waders fit them great. They fit properly around the legs and chest. The waders come with a belt and have reinforced legs to help with going through thick brush.