The references are to the latest spinoff of the Harry Potter series...
In this 'loose adaptation' we have the main houses of Hogfarts Academy.
The tale revolves around the uber-positive sect of Wake Football fandom: "House of Grobendork" while the other "House of Sluetheryn" represents those 'extra special' kids always nipping at the heels of our protaganist (Hairy Pooter) played by ol' Lectrode.
In the photo we see the better half of the 'idiot twins' Sherlock and Ferlock Zippendorf. Ferlock is an aspiring 'seeker' and here he is on the pitch working on his Quizzich 'skills." You'll likely remember his announcement last year when he proclaimed "I'm taking my skills to the Quad".
Alas, with these two on Hairy's tail, as it were, the identity of ol' Lectro appears safe for the time being.