Frank and Frank are in some way developmentally disabled.
Apparently a somewhat popular theory with some fans of the series due to their slow speech and trouble understanding things at times.
Hilltop School is located in a town in New England
For one thing, it snows in the winter, and Rosemary Wells attended a school in Boston.
Doris was a bully before the cartoon
The first episode makes it clear that Timothy already knew Doris before entering school, and the raccoon does not like her very much (a feeling that is not repeated in the following episodes). But the reason is not explained. Maybe Doris was in the habit of mistreating Timothy, but she would have been redeemed in the 1st episode, to the point that she invited him to sit next to her on the bus and play with her on the playground.
In the book Hazel's Amazing Mother, by Rosemary Wells, the same author of the cartoon, Doris is in fact a bully who, together with two cronies, attacks Hazel and her doll.
Doris and Grace were rivals before the cartoon
In the episode Putting It All Together
, Doris and Grace argue when looking for pieces of the puzzle and “dispute” the cat's pink jacket. It may be a reflection of when they were supposed to hate each other. And when Timothy and Nora remember that time is running out and that they can go without the surprise (exaggerated alarm), Doris gets angry, slaps her tail on the floor and proclaims: "I WANT SURPRISE"! Then Grace, beside her, is startled and says: "I want to, too", as if she was afraid of being beaten by Doris.
A good reason why the two were rivals is that both are quite different, and not just in height and weight. Doris is a tomboy, who likes boyish things; Grace is more of a princess, and loves to dance ballet. And she is also rich.
In any case, the two become great friends in the cartoon. In the episode Two Tutu Friends, Doris goes to Grace's ballet school, and Grace comments: “It's nice to have a friend here”. And Doris is surprised: “Huh? A friend? Me? ”, As if it were crazy to imagine that in the past. Then they been on bad and Doris tries to make peace by saying, "I don't like it when we're angry at each other." It shouldn't be today...