It may be of use to the discussion to know the (exponentially) primary generators of heat in the wheel wells, by sheer mass and heat sink/radiation qualities, are the main wheel brake assemblies. Only a fuel leak would have more potential energy in this area of the aircraft.
would having Halon bottles in the wheelwell help extinguish the fire/overheat condition?
Halon will not put out a magnesium fire and due to wheel wells being poorly closed compartments, the concentration levels needed for fire suppression would be difficult to sustain - the bottles would need to be very large. Halon also reacts poorly with hot metal, including that hot set of steel brake rotors and disks that most likely was the heat source for initiating the fire/overheat condition in the first place.
So, going back to the principal source of the heat, air, and lots of it is the best way to cool the brake assemblies. Gear down = happy feet.