1)
It already said "va'Yechdal". Why does it say also "va'Yashbes"?
1.
Malbim: Basha was doing also other matters against Melech Yehudah; he ceased all of them. In Melachim I, 15:21 it says "va'Yeshev b'Sirtzah", to teach that he did not do anything else.
