Also the game never tells you that you are looking for muriel and eustac specifically, it says "Find Them" and shows 3 dog paws that are next to courage's icon.
We can easily assume that muriel and eustace take up 2 of those 3 dog prints. There is also supposedly 3 data missing rooms with a logical way to access. It is fun exploring this game and figuring out the puzzles, but none of it compares to how much I wonder what/who the 3rd missing person is
The [DATA MISSING] picture contains a message hidden unless you fix the exposure a certain way. "Father wasn't home"