'A child who she doesn't even pretend to like' may have sounded that I meant it to be this particular child, but of course it sounded like that because this is the child who is particularly mentioned here.

The children throw handkerchiefs out of the window because they want to play, and pinch because they want a reaction from the adult.

Elinor seems very one dimensional.
She doesn't know how and what to say to people not of her level of intelligence. Harriet Smith would not have stood any chance with her, of friendship or company.
The Steeles being less intelligent of course didn't know how to react and distract the chidren and arouse interest in them about something.
Elinor being intelligent, should have told the children a story or something, or played a game.
She would have seen a miraculous change in them then. Children are so malleable.