1)
Where will they dwell?
1.
Radak: Yehudah will dwell in Eretz Yehudah and all its cities. "Bah" applies also to v'Chol Arav (it is as if it says uv'Chol Arav).
2.
Malbim: In Tzedek and its residence. I.e. They will be full of Tzedek.
2)
What is the meaning of "Ikarim v'Nas'u ba'Eder"?
1.
Radak: Farmers, people who work in fields and shepherds will travel in them from place to place, and will not fear.
2.
Radak citing Targum Yonasan: Farmers and people who travel in groups.
3.
Malbim: Also farmers and even transient shepherds, who are normally thieves (they graze their animals in others' fields) will dwell constantly in Neve Tzedek.
