Yes, you got everything right!
Mark is supposed to be the character that tells misleading information unknowingly, but there is an important piece of information he gives.
Click to see spoiler
It hints at the Mrs. Wilson’s fear of blood, or anything that resembles it, and after getting that information, the player can use the red paint in the storage room.
As for the ending, it’s not properly explained because this is a part of a larger idea I had, but since there wasn’t much time, I had to make it shorter unfortunately.
Thank you for playing!