After Stewie Potter went viral, the most common search in Google relating to it was "Stewie Potter Episode 2." A search more popular than simply "Stewie Potter" itself.
When the sorting hat makes his judgments based on color coordination and thinks Stewie would "look great in red and gold," he's actually referring to Stewie's normal color combination of his red and yellow overalls.
When Stewie and Brian arrive to Hogwarts via boat, Stewie's rant about WiFi at Hogwarts was complete improv by the creator.