I think Princeton is an inside/outside attack as in it runs the offense through the bigs too, but with a bigger focus on kicking it out to the open man for outside shots. Compare to the Orlando Magic when D12 was still there, they surrounded him with 3 point shooters so he had all the spacing he needed to operate.
Also, shots/FT's taken isn't the whole picture to find out how involved a player is in the offense. If the player gets an assist or TO he was also involved in the offense. Your bigs didn't have many assists, but maybe their passing wasn't high enough to immediately create an opportunity after their pass, but 1 extra pass was needed so the guard got the assists, while the big initiated the offense. If you look at our last NT game, our C didn't take many shots but had the most assists:
(39126)