Suggestions by @user_14999

Jim Carrey

as Old man mcgucket in Gravity falls

Score: +1

Alex Hirsch

as Bill cipher in Gravity falls

Score: +3

T.J. Miller

as Robbie in Gravity falls

Score: +1

JoJo Siwa

as Mabel in Gravity falls

Score: 0

Kevin James

as Soos in Gravity falls

Score: +1

Alia Shawkat

as Wendy in Gravity falls

Score: +1

Nick Offerman

as Grunkle stan in Gravity falls

Score: +1

Gaten Matarazzo

as Dipper in Gravity falls

Score: +2