Other mistake: When Buddy reaches inside the fuse box, after Finch puts snow in it. They cut right from him pulling it out to show his hands and there is a snowball in his hands. We do not see a snowball in the fuse box and he does not have time to shape one.
You can see Buddy and Finch's stunt doubles in the ice skating scene. And when they are showing a close up of them you can tell that they are not really ice skating, but just doing the ice skating movement.