1)
What is the meaning of "va'Yrapu"?
1.
Rashi: This is like va'Yrap'u (with an Alpeh, they cure). Radak - here, the root has a Hei at the end; the meaning is the same.
2)
Why does it say "Al Nekalah"?
1.
Refer to 6:14:1:1-3 and the note there.
2.
Malbim: One who denies Torah and Nevu'ah thinks that he is totally healthy. If he hears a Navi's rebuke, he contradicts the Nevu'ah. (Therefore, he does not realize that a serious cure is needed.)
3)
Why does it say "Shalom Shalom v'Ein Shalom"?
1.
Refer to 6:14:2:1-2.