So I bought four Mr Z Child bodies from Giantoy, they arrived after one week. They are sold out at the moment.
https://giantoy.com/products/1-6-mr-z-child-jointed-figure-body
There aren't really children heads available separately, I once bought the 'monk head' on ebay which might be a customized copy of the Aikido kid. I made a silicone mold from it before I put brown hair on it.
Left: customized "Wolf Boy" figure, the first child figure I bought as it was affordable unlike these lakor babies.
Right: Mr Z child body with the customised "Monk head" and some place holder wrapping. Mr Zs are slightly taller and has bigger feet.
Look at the march 14 2020 post for more on monk and wolf.
They come with multiple spare hands and pegs etc. All very tight. Three bodies had very hard feet and hands that could only be attached with heating, another body had softer hands and feet
In preparation of the bodies I downloaded multiple 3d models of busts and statues depicting children from the Scantheworld project on Myminifactory. They 3d scan museum sculptures from around the world and make them available for free
I cut and scaled the models and added holes before printing.
I have 7 different sculpts now and one baby sculpt.
Some are better, some worse. They are all boys I think but should work for all genders.
Here with baby/small child sculpt on obitsu body. The weird pink one with the cap is one of the seven printed sculpts, but primed. The clothing is from the wolf boy set and fits the slightly larger Mr Z.
The bald one in the middle is a resin clone of the monk, but it had some bubbles and ears were damaged.
These are mostly first drafts of course, will update some time with size comparison to adults and painted heads etc.