“Having heard this news from the king, the Buddha delivered a sermon based on the Mahā Dhammapāla Jataka”
- According to your link, that statement refers to the occasion when the King attained the Anagami stage. He had already attained the Sotapanna and Sakdagami stages before that.
- The Buddha may have referred to a Jataka story where the two of them were born in a family, but I cannot see how one can attain the Anagami stage just by listening to a Jataka story. It is just an account of a past life.
- I am not sure what the point is. Are you saying that magga phala can be attained without comprehending the Four Noble Truths/Paticca Samuppada/Tilakkhana but just by listening to a Jataka story?