A 16 film radiographic survey consists of the 12 film survey and the addition
4 film survey requires 2 anterior occlusal and 2 bitewing radiographs.​
8 film survey requires 4 posterior, 2 anterior occlusal and 2 bitewing radiographs.​
12 film survey requires 4 IOPAs for posterior teeth, 4 canine IOPAs, 2 incisor IOPAs and 2 bitewing radiographs.​
16 film survey requires 4 permanent molar radiographs additional to the 12 film survey.​

Ref: Principles and practice of Pedodontics by Arathi Rao
4 canine periapicals
2 posterior bitewings and 2 occlusal
4 permanent molar periapicals
2 posterior bitewing, 1 OPG and 1 Lateral cephalogram