1)
Did they take all his Kelim?
1.
Radak: They took his remaining clothes and weapons. The Amaleki took his crown and bracelet (2:1:10; Mahari Kara - some say, his Tefilin).
2)
What is the meaning of "Levaser Beis Atzabeihem v'Es ha'Am"?
1.
Malbim (9, 10): To thank their idolatry. There they put his Kelim and his head, like it says in Divrei ha'Yamim 1 10:10. Because the Aron cut off the head of their idolatry (5:4), they put the head of Yisrael's king [there] in Beis Dagon. "Levaser... Es ha'Am", they hung his body in the wall of Beis Shan.