Plot hole: Near the end, when Ice asks to say goodbye to the kids in the hotel room, the kids have on their pajamas, yet their luggage was left on the train earlier in the day. It is unlikely that they would have gone to the train station to get their belongings following the chaos of the Christmas party.
Suggested correction: They have backpacks so their pyjamas were probably in their bags.
In a scene right after the train scene the kids tell the mom that Nick lost their luggage. The mom may have picked up some pyjamas for the kids after learning that they lost their luggage.