I think Selective Color seldom works... and I don't think it works here! Sorry!
I have only seen four or five images that I thought worked in SC my entire life... but it is very popular with new photographers, since it is so easy to do.
Aside from the SC, what remains is the backs of heads, distracting backgrounds, and harsh light.
Not to say these aren't interesting, just not necessarily to strangers. Both would gain in general interest if the object of the children's gaze was more apparent. They could both use some fill light from a flash.