The site www.ancientmexicanwisdom.com is a real site owned by Warner Brothers.
During a chase scene with the monster, the gang can be seen in front of a movie theater. The showing at the movie is "Legend of the Vampire". This is a nod to Scooby-Doo and the Legend of the Vampire (2003), which came out a few months prior.
Fred reveals to Alejo that the reason why Shaggy eats so much and doesn't gain any weight is because he has a high metabolism.
Chiquita, the chihuahua Scooby falls in love with, bears a close resemblance to Disney character Angel from Lady and the Tramp II: Scamp's Adventure (2001). This is because both their outlines look a little similar to each other, both have similar eyes and are both blonde or creamish in color, only Angel has a puffier coat and has blue eyes and Chiquita has a smoother coat and has brown eyes.