1.) Every time I see a picture of a spied or some sort of visible piebald with a spider trait, the whole snake is white with a colored head. Just a coincidence, or is that a common thing?

Most Co Dom mutations when bred into pied result in a more white snake with head pattern the select few that eat up all the white and show a lot of pattern down the rest of the snake are Enchi, Pin, and a few others i cant remember.

2.) Granite.... what is it? It looks like a normal to my untrained eye.
3.) Same goes for Yellowbelly.

I have no clue what to look for in granites to me they are normals and not worth buying as a single gene. YB's can be either stunners or very bland but the big key for me is the belly pattern is really dirty and the sides of the belly have a sort of pixelated pattern.