Other mistake: Two goons almost caught up to Jimmy's Suburban when Natasha was driving. It isn't clear what the distance was between the vehicles, but close enough to see the other's vehicle. Natasha slowed down so that she could roll out of the driver's side "unnoticed" - and she somehow managed to do so. (00:47:18)
Other mistake: Food products used for a snowman's eyes, nose, and mouth (olives, cucumber, and ketchup, respectively) do not stay intact or unchanged over a 1-2 day period, if at all. [The idea is too absurd to categorize as a "deliberate mistake."] (00:48:33 - 00:57:00)