she only bleached it once, when she went platinum blond [i thinkOh yeah it is quite blonde. But she usually bleaches it I think? In the Prada picture you posted I think that's her natural hair color and it just looks darker because it's up.
^^She seems quite short compared to the other models in the pics, plus considering she's wearing heels while others aren't. I saw her in real but she didn't appear to be that "short". She's probably like 1m75 I guess?