Any other colors are fine, I was perplexed at the request for halal hair color.....

They are using henna rather than color as this was the practise of the Prohpet (PBUH). They can use that Grecian stuff we get back home (as long as it isnt the black stuff) and they are still within Islamic guidlelines (goes for men and women).
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"Diplomacy is the art of saying 'Nice doggie' until you can find a rock - Will Rogers"