1)
Why does it specify Yerushalayim and Yehudah?
1.
Rashi (7): I did not exile them yet. (Radak - the other 10 tribes 1 were already exiled when this Nevu'ah was said. They were exiled in the sixth year of Chizkiyah.)
2.
Malbim: Yerushalayim is the capitol, and Yehudah did not sin yet.
1
Radak (7): "Yehudah" refers to Yehudah and Binyamin (Binyamin was not included with the 10 tribes).
2)
Will Yerushalayim and Yehudah judge about themselves?
1.
Rashi (7) #1: Yes - also they did [like Adam]!
2.
Rashi (7) #2: No, they will judge about the 10 tribes (Malbim - and Malchus Efrayim).