Visible crew/equipment: When Shane is talking to Mrs. Plummer before she leaves, throughout the scene the camera man is reflected in her window (he is in black, not to get confused with Shane's white shirt) and as the car drives away the camera is shown backing up in the black door.
Visible crew/equipment: When Shane is in the car with Zoe, he yells "Go!" and the car takes off past the camera. If you look very carefully as the car moves past the camera, you can see the camera reflected in the car window very clearly. (01:02:05)
Visible crew/equipment: When Shane and the kids are going home you can see a camera's shadow on the van.
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