So the answer to your slit question I can not answer they had to draw that because if they tried to photograph it they couldn't if they can see the slits at the same time as the interference pattern it will stop.

You can build one and try and take a photo of it yourself ... it's like trying to find the end of a rainbow smile

I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.