3. Stan's Siblings Theory 1
This chapter by Prez Cipher
One of the most popular theories is that of Stan having a twin brother named Stanley. Stanley would have been the owner of the room with the carpet and the owner with the glasses as well as the one that came to the door in "The Time-Traveller's Pig." I mentioned him before in my journal theory.
First, let's analyze the facts. Stan is the great-uncle of Mabel and Dipper, and they share a surname with him, so they would have to be related to him through their grandfather on their dad's side. Many people assume this to be Stanley.
Now, this theory has nothing to do with Stanley, but I like it.
I believe that Mrs. Gleeful may be the younger sister of Stan and Stanley. She bears a slight resemblance to Mabel, and her vacuuming is remniscent of Sweater Town.
Oh, and a little more!
Stan openly shows more affection to Mabel than he does Dipper, so maybe Mabel reminds him of his missing twin...?
Okay, I pass this to Laami if she wants it.