Wow. This sounds FANTASTIC.
Well, first, I think there’s no reason why you couldn’t go ahead and do her regular hair, since Dinah traditionally wore a wig or dyed it. There’s no good reason why you couldn’t have one of her traditional blonde hairstyles.
However, I think it would be fantastic to actually present Black Canary with your own hair, as seen in your avatar. An Hispanic Black Canary with naturally dark hair sounds freaking awesome, and the hair in your avatar would be perfect for that. I know Hispanic women have every kind of hair color, but I wouldn’t change a thing (again assuming that’s you in your profile photo, forgive me if I am mistaken). Seriously, your hair is the perfect length and body to look spectacular as the Canary. I say flaunt it!
All I know is, we’re going to need pictures. :)