Reading with a 4 year old, the questions were just what we have always had with Madeline. 
 There's a scary part. Yes, there is - should we read it slowly or dangerously? (We've read Fox in Socks) 
 Why is he a skeleton face? He is trying to be scary. Is he scary? 
 Is the hat a bad hat? It's a way to say he is being naughty. Do you think he is doing naughty things? 
 Do you think he will keep being naughty? 
 Madeline looks angry. Is she angry because he is being naughty or because she is scared? 
 Wait a minute, we know who this is! 
 It's Pepito! (We have already read Madeline and the Gypsies where Pepito is a friend) 
 Is Pepito Madeline's friend the first time she meets him? Why not? oh, because he is being naughty, ok. 
 How is Pepito going to become Madeline's friend? Let's see. 
 For us this is a story about first impressions, and changing relationships. We bring our own reactions to friendship, and both people in a friendship change. Sometimes people we don't at first think of as friends become our closest friends. (Shout out, JLN) 
 We'll keep reading it, talking about things to be scared of, and talking about what makes friendship.