When Carl brings Estelle down the aisle, no one is standing for the bride.
When Carl and Estelle reminisce about the bicycle, they can be seen clasping hands when the camera focuses on him. When it focuses on her, her hand is suddenly free and she takes hold of his again.
Fletcher Thomas introduces Eddie to his father, who is called "Skippy." Steve subsequently enters from the kitchen, and addresses Fletcher's father as "Skippy." Steve was not in the room when Fletcher and his father entered, and could have had no way of knowing what the father's name was.
Carl says that he is the firstborn son but that wasn't true in season 1 when the kids throw a party while the adults are headed to Sheboygan. He referred to Darryl as his big brother.