We always have big carbon dioxide extinguishsers on the dispersal. If the engine catches, then the advice is to open the valve fully and direct the flow into the engine from as close as you dare!
For accessory compartments there are 'fire access' panels on the cowling, indicating where extinguishant should be directed if the on-board systems fail to quench a fire.
Pulling a fire handle shouldn't stop an air-start engine dry cycling, as it is intended to shut off fuel, oil and electrical connections.
As far as I'm aware, fuel systems should have two fuel valves in line from the tank to the engine, so there should always be two valves able to check the flow of fuel. Maybe that's changed on newer aircraft, as I can't see how else the A340 / A380 could be in a situation where they cannot shut down their engines?