2) No, she isn't. Philipa is going to decorate the house.
3) No, they aren't. Luke is going to organise the music.
4) Ally, Philipa and Luke are going to do the shopping.
5) Yes, he is. Luke is going to prepare the snack.
6) No, he isn't. Ally is going to inform the neighbors.
7) No, he isn't. Ally and Philipa are going to make party hats.