I feel that your composition is still too static, and the pyramid shape is not a good idea, as the age differences between the children is great enough that it looks disproportionate, because of the difference in facial size and shapes. I actually prefer your original composition, I would merely bring everyone closer together, so that your three children become a single "family" unit.
Here is my "take" on a composition that allows a bit more for the older child to be given a bit more recognition of her age, while still keeping this a family portrait.
I would also suggest that you get more pictures to work with, preferably a full frontal picture of each child, as well as 3/4 shots facing both directions. This will help you immensely in facial proportions between the three (size will be "fudged" a bit for viewability, that's "Artistic License," but you want them to look like they are all from the same family, a challenge for most facial portraits). At present, the two older children are both facing to their right, the baby, not quite as much, which throws the balance of the composition off a bit, and for you to "creatively" redraw their pose is both time consuming, and skill challenging, more than called for, as scratchboard is demanding enough, that you should have the easiest references to work with.
Hope this helps, rather than adds to the confusion.