Several times, when someone hangs up on Freddy, a dial tone is heard from his cell phone. Dial tones are only heard on land lines.
When Fred Sullivan senior elbows his son, he can clearly be seen doing so in Freddie's nose. However, if you look at the close up of Freddie's mouth you can clearly see Colson Baker biting down on a blood squib to create the effect of him bleeding from his mouth.