Arachne could be used to showcase Hubris and how excessive pride and arrogance to lead to one’s downfall.
For Daedalus and Icarus maybe you could possibly mention the importance of listening to a superior, or how man should not reach for things that are out of his grasp or maybe the concept of fate ??? The third prompt should come to you after you connect these themes with the two myths, as they are timeless lessons about the fatal flaws of humanity!!