I wouldn't want to rely on a generator, you get much more pressure and gpm from a gasoline powered fire pump then you ever would with just an electric pool pump.

You have to factor in the head and friction loss of pumping water vertically to power the multiple sprinklers and 1.5" fire hose with a nozzle if needed, which I would not do without.

With a fire pump you could also utilize a tank truck if you have no pool, or alternatively you could install a cistern poly tank.