Mute Dipper (Killdip/Billdip/Willdip)

What if story?...................
What if the twins with to Gravity Falls at the age of 9? Everything that happen in the show of Gravity Falls happened to them, they were just 9 years old. Gideon was 6 years old and still has a big crush on Mabel. Saving their Great uncle Ford and fighting Bill Cipher. The twins parents always hated Dipper because of the secret. What is the secret?...........
Mabel was still upset that Dipper almost stayed in Gravity Falls and decided to tell their parents. What happened in Gravity Falls with some Lies. They get mad and started to abuse Dipper. Mabel started to bully Dipper just because he was really smart. Dipper stop talking to everyone for 6 years. They go back to Gravity Falls at the age of 16.
Bill Cipher came back after 5 years of being destroyed in his triangle form but waited until the Cipher wheel could be formed to get his revenge on all of them. Bill Cipher is in human form and in human form he look like he is 19-20 years old. He not working alone, his brothers are there to help him.