Everyone on the list of people invited to the party was just to show Arin how special he was, as the boy hadn't had any access to the outer world till he started going to the play school a mere three days ago. And even after going there, he didn't really want anyone from there in his territory, as they all had unknowingly hurt the poor kid's soul by asking him about his dad! So he didn't want to talk much with them- making friends with them was quite an unacceptable deal.
But now, Arin had a dad; and he would show him off to everyone! He was quite habituated...