I agree with the picture. The other explanation as Lucy being a Gryffindor, Susan a Slytherin, Edmund a Ravenclaw, and Peter a Hufflepuff I see the point but I feel like the original picture here is perfectly assigned.
I am a Hufflepuff, and I am so over the comments of "Oh, you're the leftover! You're in the stoner house! keep pissing me off and you'll see what an angry badger can do.>>> absolute best Hufflepuff comment I've seen. I'm a true Gryffindor