Love the pictures! Is it the darker shades that make secret a sooty palomino? I always thought palominos came with blonde manes - I'm a bit old school you see.... my instructor is from way back when there were only ten colours, you rode in a snaffle or Pelham and god forbid you got on without a hairnet.... And this was only ten years ago! Note I said she is now retired
We understand genetics better now. Guess what - there's only two base colours (chestnut and black) everything else is other genes altering the base colour.
Yes, sooty puts darker hairs in. A normal pally is a golden colour with a white main and tail. Note Haflingers are never palomino as the cream gene is not in the breed, they are flaxen chestnut but they can look very pale due to a different gene (pangare, which also gives exmoors their mealy muzzles).