1)
Why were they in a bad state?
1.
Rashi: The Nochrim looted and plundered them.
2.
Malbim (2): The Pachos oppressed them.
2)
Why did they discuss the walls?
1.
Rashi: The second question was about Yerushalayim, i.e. the walls and gates. They answered the first question (about the people who remained), and then the second.
3)
Why was the wall breached?
1.
Rashi: It was breached before [at the time of the Churban]. Now, Yisrael built only the Bayis, but not the walls.
