1)
Which vows will he pay?
1.
Radak: The vows that I made when I fled and was exiled, if Hashem will return me to my house.
2)
What is the meaning of "Negdah Na l'Chol Amo"?
1.
Rashi: In front of the entire nation. Radak - "Na" refers to Ashalem, and not to Negdah. The Lamed in l'Chol is extra, like "Hargu l'Avner" (Shmuel II, 3:30), "veha'Shelishi l'Avshalom" (Divrei ha'Yamim I, 3:2).