After Twitty is captured by Miles on the island he says that his name is "Lars Honeytoast" which is the false name he gives to the illegal shoe salesman "Scabby" in the Even Stevens episode "Quest for Coolness".
The graduation robe Principal Wexler wears in the opening scene has three stripes on the sleeves and two vertical stripes down the front, the symbol someone with a doctorate wears at a graduation ceremony. The principal does not have a doctorate.
When Ren and Louis are fighting to get in the royal bedroom, Louis knocks off Ren's pineapple hat. In the next shot, the pineapple hat is still on her head.
When Ren and Louis are fighting about the perfect room with a view, you can see a fan atop the screen. This was after Myles said there was no electronics on the island.