When attempting to return to the North Pole via the flying cart, Cal instructs the horse to fly higher, taking them above the clouds and out over the lake. When he'd seen the vortex the drones were using earlier, it was very low to the ground, just above their house.
It is revealed that Scott Calvin is the 18th Santa Claus. In The Santa Clause 3: The Escape Clause (2006), Santa's snow globe vault had a snow globe representing each previous Santa and there were 60 of them.
"Seventeen" doesn't resemble the Santa Claus that fell off of Scott's roof in the original film. His build and suit are visibly different.
At the end of the previous episode when the hand grabs his shoulder Scott looks down at the hand but in the start of this episode when the hand grabs his shoulder he does a double take to his family and then turns his head straight back to look at the person and never looks down at the hand.
When the Calvin family is attempting to fly the cart into a vortex, Cal, the only one who can see the vortexes, has his eyes closed due to his fear. The horse tells him to open his eyes and he responds. Cal is not supposed to be able to understand the animals' speech. That's Sandra's magical ability.
It is stated that Scott Calvin was the first human Santa Claus, with all previous Santa Clauses being "ethereal beings." The gathering of Santas includes St. Nicholas, who was human. The story here even says that it was his generosity that brought Christmas magic into existence in the first place.
The role of Santa is said to be passed down via the Santa coat, which was made from the original St. Nicholas' robes. The various Santas seen wear many different outfits and robes, many of them not even the same color as the coat.
Cal and Sandra laugh at the notion that they may have magical powers, even though he has been experiencing premonitions and she has been talking to animals.
Bernard says that he and Vanessa Redgrave are several hundred years apart. It was stated that she is 85 and he is over 1600, making them more than 1500 years apart in age, which is far more than several hundred.