Perfect Number (The first "perfect number" is 6 that is Angora's age)
Pass -- good clue
Metallic coats in blood. (Akhal Teke's are known for a metallic shine to their coat)
Fail -- I don't think this is widespread knowledge, I've never heard of it before anyway, and lots of horse breeds can have shiny metallic coats. It just wasn't a clue that made sense to me, even after the reveal.
Blood didn't hold. (Her family/her left her)
Pass
Empty crown should fall. (She is an equine, her "crown" is empty. Her coloring is gold.)
Fail -- I'm not sure how gold color applies to this? I also didn't get the species ref with this, I took it as more of a rank ref, which I think has to do with the way your wrded it. I agree empty crown can be a good non-unicorn clue, but in this scenario it seems misdirecting and just didn't 'click' for me.
Magic or force permitted any time, aside from death.