Regarding your third question, I suggest that two things be done to help protect your equipment:
Keep the fuel tank full when not in use. Ethanol can absorb moisture from the air so if the tank is kept full, then there will be very little air in it. When ethanol combines with moisture, the ethanol separates from the fuel and sinks to the bottom of the fuel tank. It is this concentration of ethanol at the bottom of the tank where it can be drawn into the engine that can cause issues such as corrosion of the fuel system. It also could make the engine run rough.
A fuel stabilizer such as STA-BIL can be used every time the equipment is refueled. This can help keep the gasoline from oxidizing and also help prevent the ethanol from separating from the gasoline. Add the stabilizer to the fuel storage container used to refuel the equipment. Be sure to use fresh stabilizer in gasoline that is younger than 90 days old for best results.