Shauna is blatantly Lisa.

I would have Psy as Bart and Steve as Milhouse.

Pantz is Dr. Hibbert.

I would actually have Yeru as Sideshow Bob because he's rather articulate and pedantic. xD Cuch doesn't strike me as a man of the arts.

Wyllius would be the definition of Willie but he's not around anymore, but Cuch is worth a shout. I know he's not Scottish but personality wise he's a fine fit. Alternatively, Bleys.