In this film, Santa's reindeer are referred to as "girls" and "ladies"; makes sense, as female reindeer are the ones who keep their antlers thhe whole year round (males shed their antlers in early December).
The Snowlem army has to hide in an ice cream truck when storming the beach in Aruba. It's not just the temperature that would affect them, it's the salt.
Cal's ability to shrink and grow might be a reference to how elves of legend could be taller than the average human (think Tolkien's elves) or smaller (think Santa's elves...outside of this movie) given which story is being told.
As funny as it is on its own, Santa saying 'look what the cat dragged in' to Krampus after the latter comes into the picture in time to help save him is actually surprisingly appropriate considering who captured Santa here in the first place. For in the same legends that Gryla and her sons are from, they have a giant pet cat called the Yule Cat. And assuming it wasn't Adapted Out (by virtue of it not even being mentioned), there's a good chance that Krampus personally interacted with the Yule Cat during his past history with Gryla.
Cal states that the staff at the North Pole complex are constantly working 364 days a year, but get Boxing Day off, which makes perfect sense; with Christmas the day they're constantly working towards the rest of the year, the best time to give them a day off is the day immediately after Christmas, before they have to start preparing and training for the next year.
Nick points out that it's not his job to change people, which is correct - he can judge people as naughty and nice, but it's up to them to hear his judgement and fix their flaws and/or stay good, or they can just ignore it. As he says, "People change themselves."
