1)
Why does it say "El ha'Pelishti"? It should say Al ha'Pelishti!
1.
Radak: This is like Al ha'Pelishti. Refer to 17:49:1:1.
2)
Why does it say that he used Galyus' sword to kill him?! Verse 50 says that he already killed him via rocks!
1.
Radak: Our verse means that he had already killed him via rocks. He used the sword to cut off his head.
2.
Malbim (50): Verse 50 means that he was stricken with a blow from which he would die. Our verse means that he completed his death. The four letter root 'Moses' refers to final death.