I would try suction idea through dipstick hole. I like the kerosene idea too.
Another quick ( probably unsuccessful) idea to avoid removing pan.
Assuming no oil in engine.
Tilt engine at strong angle with drain hole at lowest point.
Blast highest possible pressure compressed air into dipstick hole where plug fell.
This just might be enough to get the piece to rattle/ move towards drain hole, at least to a point where you cold retrieve it.
Perhaps even mount vacuum to oil plug drain hole with a good seal (but you'd need a clean vacuum bin to see the piece to know if it got sucked out)
Spend no more than 60 seconds or so on above idea
