Susan is very fond of toast and marmalade, but on a cold winter's morning she enjoys hot porridge with lots of brown sugar and maybe a pinch of cinnamon too.
Romilda tries to skip breakfast because it's, like, totally fattening and she wants to lose weight. She used to eat chocolatey cereals, but now she'll maybe have a banana or a yoghurt because aren't they, like, what celebrities eat for breakfast??
Draco either has plain cereal or toast (with maybe a boiled egg if he's feeling hungry).