Bart's hair is its natural red color without the sun. However, this contradicts "I Married Marge" where Bart was born with yellow hair.
In the scene after a car leaves the Simpsons' house, you can see that Otto and Agnes Skinner go out of a closed place meaning they are making love inside it.
The last episode to feature Ned as a landlord only for Homer to humiliate him was "Home Away from Homer".
Homer said they started Mardi Gras was two days before Bart was born which would make his birthday February 11. However, Bart's birthday has been stated as either February 23 (which is non-canon) or April 1.