Other mistake: In the scene where it's talking about the hottest summer the city's ever had (or something to that effect) some neighborhood kids are frying an egg on the sidewalk. The problem is, they're sitting and kneeling on that same sidewalk with their bare legs, and don't seem to be in any pain or discomfort.
Other mistake: When George is holding his newborn baby and his grandchild, you can see that the babies are actually dolls and not actual babies. I guess it made it easier for him to hold in some shots.
Other mistake: When George and Nina are driving to Annie's place to tell her about the pregnancy, Nina looks out of the window and you can tell no one is in the passenger seat. (00:43:26)
Other mistake: When George sells the house, he mentions living there for 18 years. This can't be right as it's mentioned in the first movie that Annie was 5 when they moved in. In the second movie she's 26, so that would mean they've lived there 21 years.