For the second season, David Feiss and the writers decided to include Red as one of the main characters (making him sort of the "connection" between the shows Cow & Chicken and I Am Weasel), this worked out well, as the quality of the show improved tremendously.
The way Weasel flies through the air with the help of his umbrella is obviously a parody of Marry Poppins, who did the same. Even Weasel's costume resembles hers.