Going to disagree on the gulastra plume, as that's a characteristic of sabino and this guy would just have it from his Appy genes most likely.
It's hard to tell from this angle, but I'd be inclined to say he's a bay varnish roan with a blanket. He could potentially be liver chestnut under there, but we'd need better shots to determine if his legs are actually black or not.
He's definitely a varnish roan, and I'm actually going to say liver chestnut seeing more pics as he's the same color as the colt Shay-la brought home. He doesn't actually have black points, he's the same even chocolate color all over with the typical sun bleaching on his body area making him look lighter. No black on his muzzle or tips of the ears it seems, and his mane and tail aren't black.
I am sticking to blanket - the snowflake pattern typically distributes mottles of white all over the body. He just has a very small blanket.