Stewie sings that Bill O'Reilly's Dermatologist has made it onto his Little List. However, Stewie then kills Bill O'Reilly, not Bill O' Reilly's Dermatologist.
After Stewie gets killed by Peter, his body goes flying back and ends up near a wall.
When Peter and Lois embrace and look at Stewie's body, suddenly his body is in the middle of the floor, nowhere near a wall.
After becoming President, Stewie flies his own flag over the White House, but he still has the American flag in the Oval Office. However, the American flag could be there as decoration.
When Lois gets shot in the flashback, the bullets can be seen going through her body. Yet, when she sinks down into the ocean, her shirt and back are unharmed and don't show signs of having been shot.
Peter says he has plans with the guys that night, which is the night of the trial. Peter wouldn't have had plans with his 3 friends because he was most likely being sentenced to jail for Lois's murder. Even if he wasn't, his friends were mad at him.