Based on similarities in these panels I believe that The Numbers were actually children trafficked by Mother Carmel.
Earlier, I incorrectly assumed these children with the ones eaten by Big Mom, when they were displayed chronologically before Big Mom was born. The children would have been trafficked long before Mother Carmel’s death as she is young in the frame outline.
The key visual signifier in addition to their positioning is the club over the central figure’s shoulder in both panels. If we consider that the purpose of Mother Carmel was to recruit giants to the World Government, it is feasible that the kids were used for experiments.
We also know that making children into giants is a canon thing in the One Piece world. That leads to the question of how the giants were appropriated by Kaido’s army.