Interesting conversation but a couple of points, remember you only need to remove one of the three elements in the fire triangle (I think they use four now, chemical, shouldn't be an issue in a light aircraft) to stop the fire.
Aircraft cabin fire foam is the best alternative (electrical is not an issue as max voltage is generally 32 volt RA/GA) foam is wet and will remove the heat from components and also smother reducing the available oxygen and if used correctly (not sprayed everywhere) will not obscure the view out the window.
Halon - BCF (difficult to get) is a great extinguisher but is an oxygen scavenger and as such you as PIC can't breathe either , so you say open the door or window/vent as soon as you do that the heat in the fire will reignite with the return of oxygen. I have been in an engine room (on an offshore drilling rig) with a halon un-commanded release and it is not a situation you want to find yourself in at altitude - 10 seconds and you can't breathe.
Halatron - available but as above just not as effective as Halon
All fires shut off the electrical supply but remember residual heat will still be there see point 1 above.
Engine compartment fire shut off fuel & electrical supply and get the nose down as far as you can (wouldn't worry about vne at this stage) - excess air = excess oxygen, fire will go out as it is too rich to burn, additional airflow will assist in cooling the hot areas, need to be careful on pulling out of the dive though as you may stall the aeroplane and end up with an additional problem.
Aldo