Factual error: Shane's rank is Lieutenant but his formal uniform in the hospital after he gets shot shows the rank of Captain.
Other mistake: The mom comes home and finds the Sound Of Music poster for the performance that her son is in. Louisa on the poster is a completely different actress from the one in the rehearsal scenes.
Continuity mistake: At the beginning of the film Vin Diesel is shot, presumably in the chest or torso, but in the shirtless scene during the Girl Scout troop meeting he doesn't have a single scar. (00:06:05 - 00:36:20)
Answer: Peter - 3. Lulu - 10. Seth - 13. Zoe - 16. Although the children actors were 2-3 years older than the characters they were playing (which isn't uncommon, but more noticeable at these younger ages).
Bishop73