I have always used gas oil mix just like what I run to flush the crank area out.
Nice part about these little motors is there so easy to turn differnt ways to get it flushed out.
I would think kerosene would work just fine and is a bit safer. and I wouldnt worry to much about lube roller bearings need very litte lube and kerosene does have a bit of lube to it. Or do the kerosene then just a quick rinse with some 16:1 premix once the gas evaporates it will be oliy.