I haven't gone through the whole thread for a while so i don't know if anyone found a remedy to the noise or not. I yesterday took the car to someone who is a very good family friend of the in-laws and has been their family mechanic for some decades now. A little background of the problem; the notorious tuk tuk sound from the front wheels along with heavy vibration and scratching noise when the brakes were applied. A number of mechanics could not diagnose the fault.
The mechanic I mentioned disassembled the brake assembly, removed the disk from the hub, told me to get a new hub for 800 Rs. or so. instead, I got a kabli one for 1000 Rs. as I could not find a new one. And voila! the sound vanished, the vibration vanished and the brakes are better now.
Car is a Mehran.