After giving children and toddlers inappropriate tattoos you can now give them inappropriate makeup! And I don't mean as facepaint - I've unlocked the makeup category for these age groups and made overrides for all the makeup so far so that tots and kids can use them. As with tats, if there are makeup CCs you have that you'd like to plaster on the faces of your Sim kids you'll have to go into Sims4Studio and check the right boxes to get them to show up.
There's also a handful of kid's facepaint that I made accessible to teens - elders. I mean, why not? It's that kind of project.
In addition to makeup and scars beards and freckles have been updated for kids and tots too. This is more of a "because I can" than a "because I should" thing. If you don't want hairy kids delete the hair packages.