In the scene after Grandma finds all of the tissues on Donny's bed, Todd goes into the bathroom to wash his hands. When Todd comes out of the bathroom, the light is on, but when Donny says the line about "La Vida Loca," the light is off.
When everyone is visiting the church we see chad in his USMC uniform with the correct PFC rank insignia on his sleeves. For a brief second he is seen with a Corporal's insignia which switches back to PFC in the next shot.
In the courtroom a cameraman punches young Donny in the face and calls him a dumb ass. The cameraman clearly misses Donny. He just makes a punching motion in front of Donny a considerable distance away.